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754 Cards in this Set
- Front
- Back
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When a process variable has no method of sending information to the final control element the system is known as a) an automatic system |
b) an open loop system |
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An open loop control system requires a) a transducer and a recorder |
d) constant attention |
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A process variable which is adjusted in order to maintain or achieve some desired value of another variable is termed the a) process variable |
c) manipulated variable |
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A control loop controller a) does not require a set point value |
e) constantly compares input signals to the set point
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A common air pressure range for pneumatic control systems is a) 3 to 15 kPa |
e) 20 to 100 kPa |
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A very important requirement for a pneumatic control system is a) maximum transmitter output signal pressure must be maintained |
b) air supply must be clean and dry
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The apparatus which converts current signals to pneumatic and pneumatic to current signals is called a a) converter |
d) transducer |
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A control device which will change one form of energy into another form of energy is the a) controller |
d) transducer |
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A device which will cause a visible light signal to become an instrument analog signal is the a) photoelectric transducer |
a) photoelectric transducer |
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A "control" should be considered as a special device which a) sends or transmits a positive rather than negative signal |
b) tries to maintain a set point |
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Automatic systems which can make decisions are termed a) annunciation systems |
c) logic systems |
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An inclined manometer is commonly used a) when very low pressures or vacuums are being measured |
a) when very low pressures or vacuums are being measured |
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A Bourdon tube is often in the shape of a spiral so that a) its final output has less travel |
d) more power and travel of the output occurs |
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When a diaphragm device is used for boiler water levelmeasurement, the boiler pressure is compensated for or off-set by a) using a bellows on the HP side |
c) applying the pressure to both sides of the diaphragm |
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One of the most widely used process variables in a system is a) temperature |
e) flow |
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In a glass stem thermometer the space above the liquid is usually a) nitrogen |
c) maximum vacuum |
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A thermocouple will produce a DC millivoltage which a) will be read on a pressure scale |
d) is not quite proportional to temperature differences |
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The Bourdon tube is often shaped in the form of a "C", having an arc span of about a) 180 degrees |
e) 270 degrees |
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The purpose of a spiral or a helix Bourdon tube is a) to increase the pressure rating |
b) to provide a greater degree of rotation |
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Glass thermometers with a mercury fill are sometimes pressurized with nitrogen so a) that they can be used in a horizontal position |
c) that they can be used at higher temperatures |
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Temperatures are measured by a) wattmeters |
e) thermocouples |
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The variable area meter consists of a) a fluid being measured, flowing through the tube from the top to the bottom |
d) a tapered tube in which the fluid being measured flows through the tube from the bottom to the top |
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A bimetal thermostat reacts to changes of a) pressure |
e) temperature |
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When a float is used for measuring level, and installation within a vessel is impractical, a device often used is the a) float manometer |
b) float cage |
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Relative to flow, velocity is kinetic energy and when velocity increases, the a) pressure and potential energy, will also increase |
d) potential energy in the form of pressure will decrease |
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Liquid must be in its vapour form a) in order to measure density |
c) when a chromatograph is being used |
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A chromatograph uses electronic devices which a) utilize electrical current as a measurement base |
b) have inverse resistance properties relative to temperature |
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The electrical output from a thermocouple is measured by a a) milliampmeter |
d) millivoltmeter |
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A thermocouple consists of a) a filament that is compared to the object being measured |
b) two dissimilar wires connected together to form a hot and a cold junction |
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A flapper-nozzle assembly is basic to all a) controllers |
b) transmitters |
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The nozzle receives a constant air supply pressure of approximately a) 140 psi |
c) 140 kPa |
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The output pressure signal of a transmitter relay is usually a) direct and proportional to nozzle pressure |
a) direct and proportional to nozzle pressure |
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A two-position controller compares conditions to a set point and a) will start or stop a process |
a) will start or stop a process |
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When controller output is proportional to the amount of deviation, the controller is a) derivative only |
e) proportional |
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A proportional only controller a) cannot maintain maximum value of the final element |
b) cannot maintain set point except at 50% |
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A recorder utilizing a spiral Bourdon tube will have a pen movement a) linear to the tube travel |
b) proportional to the change in tube pressure |
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When a recorder receives a signal from a transmitter, therecorder incorporates a a) signal reverser |
d) capsule or bellows |
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When an operator uses CRT displays, the computer control panel a) often has a number of dedicated recorders |
a) often has a number of dedicated recorders |
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A control valve a) is always normally closed |
b) is a form of variable resistance in a piping system |
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A valve actuator a) cannot be reverse acting |
d) position is a function of controller output |
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Most solenoid valves are unlike globe valves in that upstream line pressure will a) act to open the valve
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d) act to close the valve |
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On a packaged boiler a number of electrical switches connected in series can be categorized as a) controls |
b) interlocks |
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A combustion air proving switch a) senses O2 content of the air c) detects O2 in flue gas e) senses air temperature |
d) senses windbox pressure |
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A lead sulphide cell is sensitive to IR rays and a) its resistance to current flow varies inversely with ray emissions |
a) its resistance to current flow varies inversely with ray emissions |
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To operate the type of flame failure device which incorporates a lead sulphide cell, it must receive a) heat from flame |
c) infrared rays |
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The function of a flame failure device is to a) shut off the fuel supply when the pressure gets too high |
b) shut off the fuel when the burner flame goes out |
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Which of the following is a flame sensing device? a) thermopile |
e) scanner |
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A flame failure device a) must be installed on every high pressure boiler
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d) will shut off the fuel to the burner |
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Boiler modulating feedwater control flow rate depends on a) level set point |
e) set point, level, and valve position |
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With single element feedwater control the level transmitter a) received by a final element |
b) proportional to drum level |
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The second element of a two element feedwater control system compensates for or offsets a) level variation |
e) shrink and swell |
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A boiler control transfer or selector station a) can be used to manually override automatic control loops |
a) can be used to manually override automatic control loops |
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An automatic feedwater regulator is used to a) take the place of the boiler feed pump |
c) maintain a constant water level in the boiler |
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In a two element feedwater control the following items are measured: a) boiler water level and steam flow |
a) boiler water level and steam flow |
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On a steam boiler with single element feedwater control, the following item is measured: a) steam flow |
c) boiler water level |
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An automatic boiler ON-OFF or operating control switch has an adjustment for cut-in or cut-out value and another for a) a differential between the two |
a) a differential between the two |
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A packaged steam boiler modulating combustion control system will routinely a) maintain drum level within a desired range |
e) maintain boiler steam pressure within a desired range |
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Modulating combustion control will a) change air and fuel flow proportionally to steam pressure change |
a) change air and fuel flow proportionally to steam pressure change |
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Modulating combustion control will a) change air and fuel flow proportionally to steam pressure change |
a) change air and fuel flow proportionally to steam pressure change |
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Modulating combustion control on a heating boiler is accomplished by a) shutting down or lighting up the burner as pressure or temperature rises or falls |
c) changing the amount of fuel and air to the burner |
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A float operated low-water fuel cutoff has its switch separated from boiler pressure by a) a float cage |
c) a flexible diaphragm |
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A mercury switch bulb is under high vacuum and contains inert gas a) so it will not explode |
b) to prevent corrosion of the contacts |
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A float operated level control a) will recognize swell and shrinkage and correct the feedwater flow |
c) is only used on small boilers |
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Overheating of boiler heating surfaces due to low water a) is the main cause of boiler failure |
a) is the main cause of boiler failure |
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A low water fuel cut-off is fitted to a boiler to prevent a) damage to the radial stays in the steam dome |
d) damage to the boiler from an overheated condition |
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The purpose of a low water fuel cut-off is to a) shut off the feedpump when the water level gets too high |
e) shut off the fuel supply when the water level gets too low |
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A low water fuel cut-off may be activated by a) lowering the water level in the boiler |
a) lowering the water level in the boiler |
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The CSA code states that a boiler not under continuous attendance must be equipped with a low-water fuel cutoff which a) must be a normally open switch |
e) serves no other purpose |
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A low-water fuel cutoff which serves no other purpose a) cannot be equipped with isolation valves |
a) cannot be equipped with isolation valves |
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A low-water fuel cutoff switch should close the automatic fuel valve(s) when the water level is a) at the lowest permissible water line |
c) 1 to 2.5 cm above the bottom gage glass nut |
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A hot water boiler low-water fuel cutoff a) should be tested weekly during routine boiler operation |
b) cannot be tested during routine boiler operation |
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The drain of a hot water boiler low-water fuel cutoff should be opened to flush out any debris a) annually |
c) weekly |
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To test a low water fuel cut-off a) call for an electrician who specializes in boiler controls |
b) lower the water level until the burner shuts down |
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The float chamber of the low water cut-off is blown out often to prevent a) the chamber collecting sediment |
a) the chamber collecting sediment |
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The most reliable method of checking or testing a low-water fuel cut off is to
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c) lower the water in the boiler to the level where theburner should cut out |
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The low water cut-off can be tested by a) raising steam pressure |
c) shutting off the feedwater |
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Automatic boiler programming controls a) must incorporate a modulating control system |
c) require an ON-OFF or two-position control switch |
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An interrupted pilot of an automatic boiler a) burns continuously, like that in a home furnace |
d) lights, completes a trial, and extinguishes after a main flame trial |
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The function of a programming control is a) to supervise feedwater supply to the boiler |
c) to regulate combustion controls during start-up |
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Boiler furnaces are purged a) so that the programmer has time to verify permissiveness of interlocks |
d) so that combustibles are fully removed prior to ignition |
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Automatic boiler liquid fuel manual valves should be opened a) prior to pre-purging |
a) prior to pre-purging |
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The operating pressure control will control the a) steam pressure in the boiler |
a) steam pressure in the boiler |
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The second from last step in an automatic boiler programmer shutdown sequence is a) timer shutdown |
c) post purge |
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With automatic fuel fired boiler programmed control the normal firing period begins approximately a) 44 seconds after FD fan starts |
c) 60 seconds after FD fan starts
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On a gas fired automatic boiler a normal programmed start-up takes approximately a) 105 seconds |
a) 105 seconds |
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During a programmed start-up if an ignitor spark is visible but no flame appears the operator should suspect a) a boiler low water level |
c) the pilot manual fuel valve is closed |
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If a shutdown occurs during normal firing of a boiler and the steam pressure is below the normal cut-out value, the problem could be
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a) the sensing line to the combustion air proving switch has broken |
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On a boiler with high-low fire control, if the damper positioning switch is in the wrong position a) the damper motor may not operate |
a) the damper motor may not operate |
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The main function of a mainframe computer system is to
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b) rapidly process large amounts of data |
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A typical use of a mainframe computer system in a process would be
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a) the operation of a modulating control valve |
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Sharing and transferring information between computers is termed
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e) networking |
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A multiplexing sequence may be repeated as high as
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d) four times per second |
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Computer "soft keying" is
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b) done to make the computer quicker and easier to use |
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A digital input computer is protected from harmful voltages by means of
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c) isolating circuits |
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Transmitters which transmit digital codes directly to a computer are known as
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b) smart transmitters |
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The common standard control modes for a plant control system are
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e) derivative, proportional, and integral |
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Inputs for logic and supervisory computer functions are mainly
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a) by switch contacts |
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Computer "Run Time Totals" are commonly used a) in graphic displays |
d) for maintenance management |
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The combustion chamber of a serpentine tube watertube boiler is a) equipped with gas power burners |
d) located below the tube |
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One of the reasons that industrial type watertube boilers are seldom selected for low pressure heating plants is a) high fuel consumption |
d) high cost |
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A membrane waterwall a) is usually not gas-tight |
c) has metal connecting the tubes |
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What limits the height of a packaged boiler is a) building ceiling height |
e) transportation requirements |
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The use of bent tube boiler designs allows the furnace wall to be lined with tubes, thereby exposing more of the heating surface to a) convection heat |
c) radiant heat |
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The bent tube boiler design allows the tubes to be attached radially on the outside of the a) furnace |
d) shell or drum |
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In a low pressure serpentine tube watertube boiler, the serpentine tubes are attached to upper and lower headers with __________ connections. a) welded |
c) threaded |
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The furnace walls in a bent-tube watertube boiler are formed by water filled tubes and these walls are called a) furnace walls |
b) water walls |
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A reason for preferring copper tubing in a tubular boiler is a) low cost |
d) corrosion resistance |
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An initial problem with the tubular boiler being used as a steam unit was a) metals which would not stand up to the temperatures involved |
b) dissolved impurities forming scale on the tube |
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An advantage of a packaged low pressure tubular or watertube boiler is a) its ability to meet load changes due to its heat reserve |
e) safety due to the low volume of water it contains |
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One of the advantages of the low pressure serpentine tube a) ease of feedwater treatment |
d) ease of replacement of defective tubes |
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One of the advantages of the low pressure serpentine watertube boiler is a) virtually no maintenance required |
c) virtually eliminates expansion and contraction stresses |
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A reason for preferring copper tubing in a tubular boiler is a) faster heat transfer rate |
a) faster heat transfer rate |
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A packaged tubular steam boiler often has a steel sheathing in front of the waterwall tubes due to a) the high radiant energy from the flame |
c) the erosive action of the flame |
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In order to keep salt concentrations within safe limits the packaged tubular steam boiler utilizes a) an automatic blowdown |
a) an automatic blowdown |
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A disadvantage of the watertube or tubular boiler is a) its long warm-up period |
b) water treatment monitoring |
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The copper tube tubular boiler a) can be gas or oil fired |
a) can be gas or oil fired |
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Sectional cast-iron boiler sections are connected with a) push nipples |
a) push nipples |
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Cast-iron boiler sections maximize heat transfer by a) utilizing as few passes as possible |
c) exposing as large a surface as possible to the hot gases |
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Boiler water legs a) increase the heating surface |
a) increase the heating surface |
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Boiler sections are held together with a) cap bolts |
d) tie rods |
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The ratio of heat released to heat transferred to boiler water is known as a) combustion efficiency |
c) boiler efficiency |
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Most low capacity cast-iron boilers a) cannot be site assembled |
c) will pass through standard size doorways |
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The steam and water spaces of a cast iron sectional boiler are a) tie rods |
e) push nipples |
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The steam and water spaces of a cast iron sectional boiler a) cast iron pipes |
d) tie rods |
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In a vertical sectional boiler the sections are placed a) one above the other |
b) side by side |
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The sections of cast iron boilers are mainly designed to a) water space |
d) heat transfer |
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The fins cast on the flat surface of the sections of a cast iron sectional boiler are used for the purpose of increasing the a) effectiveness of heat transfer |
a) effectiveness of heat transfer |
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To prevent flue gases from escaping in a cast iron sectional boiler, the spaces between the sections are sealed with high temperature a) silicon chalking |
e) asbestos rope |
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Heating boilers attain maximum efficiency only when they are operated a) intermittently at 90% of the load |
c) continuously at full load |
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Modular cast-iron boiler water flow is a) continuous through all modules |
a) continuous through all modules |
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In a cast iron modular heating boiler, the operation of the burner of each module is controlled by a __________ which starts or stops modules in sequence as load demand increases a) temperature sensor |
b) step controller |
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A cast-iron boiler disadvantage is a) it is subject to corrosion |
e) its pressure limitations |
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A cast-iron boiler advantage is a) its high factor of brittleness |
d) the choice of assembly location |
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Cast-iron boiler capacity a) is very large compared to steel boilers |
b) can be increased by simply adding sections |
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One of the earliest firetube boilers was the a) locomotive boiler |
c) HRT boiler |
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An internally fired boiler a) is less efficient than an externally fired unit |
c) has the furnace surrounded by water |
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The forerunner of the modern packaged firetube boiler was a) horizontal return tubular boiler |
e) Scotch Marine boiler |
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Initially the firetube boiler was not up to manufacturing expectations because a) too many equipment suppliers were involved in its manufacture |
a) too many equipment suppliers were involved in its manufacture |
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Smaller firetube boilers are low cost and a) have simple rugged construction |
a) have simple rugged construction |
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When a packaged firetube boiler is used as a power boiler rather than a heating unit a) it will have a much stronger design |
a) it will have a much stronger design |
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The steam pressure must not exceed _________ kPa for a boiler to be considered a heating boiler. a) 15 |
e) 103 |
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The temperature of a boiler must not exceed __________ degrees Celsius or the pressure exceed 1130 kPa for it to be considered a heating boiler. a) 250 |
d) 121 |
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To maintain high gas velocities throughout all gas passes in a four-pass firetube boiler, the cross-sectional area of each succeeding pass is a) increased |
b) decreased |
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A firetube boiler commonly used for hot water heating systems in residences and small apartments is the a) Scotch firetube packaged unit |
c) steel plate vertical unit |
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A steel plate vertical firetube unit is divided into two sections and the upper part is often called the a) reversing section |
e) heat exchanger |
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When the hot combustion gases travel through boiler tubes which are surrounded by the boiler water, the boiler is called a a) watertube boiler |
e) firetube boiler |
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Packaged firetube boilers a) are not very rugged relative to portability |
c) require relatively small building volumes |
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When a packaged firetube boiler is used as a hot water unit a) it can be constructed of thinner material for a given pressure |
d) forced circulation is required |
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The advantages of a packaged boiler are: 1. lower freight costs because of less handling 2. lower initial cost because they are mass produced a) 1, 3 |
d) 1, 2, 3, 4, 5 |
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The chief advantage of a packaged boiler is that it can be a) operated without supervision |
c) mass produced |
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One of the advantages of the firetube boiler over the watertube and tubular boiler is in the a) fuel and combustion area |
c) water treatment area |
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The advantage of a vertical firetube boiler is that it requires a) very little floor space |
a) very little floor space |
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The reducing of oil into very small particles is termed a) fluidization |
d) atomization |
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Before atomization can occur, heavy oils are heated to approximately a) 203 degrees C |
b) 95 degrees C |
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An air atomizing burner utilizes an air pressure of approximately a) 15 kPa |
e) 100 kPa |
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An air atomizing compressor is usually a) a variable displacement type |
d) a positive displacement type |
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The capacity of a constant capacity mechanical atomizer is a function of a) orifice size |
a) orifice size |
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A modulating pressure atomizer has its return oil flow regulated by a) a modulating valve to the burner |
b) a modulating valve in the return line |
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To which of the following oil burners is the oil supplied under high pressure? a) mechanical atomizing burner |
a) mechanical atomizing burner |
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When using mechanical fuel oil atomization a) 70 kPa steam pressure is required at the burner |
c) high pump pressure is required |
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Oil burners can be divided into three classes: 1. air and steam atomizing burners a) 1, 2, and 3 |
a) 1, 2, and 3 |
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The compressed air used as atomizing air in the air atomizing oil burner is also called a) secondary air |
b) primary air |
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The two basic varieties of mechanical atomizing oil burners are: 1. variable capacity burner a) 1 and 3 |
b) 2 and 3 |
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A multi-burner cluster has secondary and tertiary nozzles ignited by a) an igniter spark |
d) the primary burner |
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When a greater than normal amount of combustible mixture is ignited the result may be a) a boiler explosion |
b) a puff-back |
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A fuel filter consists of a) a cartridge |
c) three main parts |
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Burner light oil supply pressure range is approximately a) 50 to 100 kPa |
d) 550 to 700 kPa |
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A relief valve is placed on the discharge of a fuel oil pump a) because the pump is a dynamic type |
b) so burner design pressure is not exceeded |
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A time delay oil valve a) opens when the pump starts |
b) opens once ignition is verified |
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In order to prevent the possibility of a furnace explosion it is important that the furnace is __________ before the igniter is energized and fuel is supplied to the burner nozzle(s). a) pre-heated |
c) purged |
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Intermediate and high fire burner nozzles have higher capacities than the primary burner nozzle a) to give greater firing variations |
e) to allow better boiler warm-ups |
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Oil flow rate to a modulating burner is regulated by a) a return line modulating valve |
a) a return line modulating valve |
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The minimum distance from furnace to oil storage tank is a) 7 m |
c) 2.1 m |
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Maximum static pressure in a fuel oil line is approximately a) 10 kPa |
e) 70 kPa |
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The main function of a gas burner is a) atomization of the fuel b) a source of ignition c) provision of O2 -fuel contact d) regulation of the fuel flow e) air flow control |
c) provision of O2 -fuel contact |
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An atmospheric burner has air entering around the burner which is termed a) primary air |
b) secondary air |
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The amount of pre-mix air to an atmospheric burner should be a) 10 to 12% |
d) 30 to 40% |
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A refractory burner disadvantage is a) high initial cost |
a) high initial cost |
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A very popular packaged boiler gas burner is the a) ring burner |
a) ring burner |
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An atmospheric burner head which is very popular on heating boilers is the a) refractory type |
d) rectangular type |
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When a gas fired burner is burning fuel properly a) it will have a blue flame with short yellow tips |
a) it will have a blue flame with short yellow tips |
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Gas burners for heating boilers can be divided into two general classes and they are the a) pre and post turbulence burners |
d) pre and after mix burners |
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The Venturi tube in the atmospheric burner mixing head has a a) gradually decreasing cross-sectional area |
b) gradually increasing cross-sectional area |
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__________ burner heads are most common for use in heating boilers. a) Oval |
e) Rectangular |
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One of the advantages of the refractory (gas) burner is the a) low cost |
b) gas and air mixture is thoroughly preheated before it enters the furnace |
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The purpose of the deflector vanes in the centre of a ring (gas) burner is to a) atomize the gas particles |
d) promote turbulence of the gas and air mixture |
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One of the advantages of using natural gas as a fuel in a boiler is a) that no storage space is required |
a) that no storage space is required |
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An intermittent pilot a) lights the main flame then extinguishes |
c) lights the main flame and remains on with it |
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The pilot burner for gas fired heating equipment can be: 1. manual a) 1, 2, and 3 |
c) 2, 3, and 4 |
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The __________ pilot is most often used on small boilers. a) interrupted |
e) continuous |
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Large capacity burners a) require high flow on ignition |
d) should have minimum flow on ignition |
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A hydramotor valve a) opens and closes quickly |
b) helps to prevent puff-backs |
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A solenoid type fuel valve a) is held closed by fuel pressure |
a) is held closed by fuel pressure |
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If the power is cut off to an automatic gas valve, the valve a) closed slowly |
b) closed immediately |
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The advantage of a motorized (hydramotor) gas valve is that the valve opens __________ thus preventing "furnace puff". a) slowly |
a) slowly |
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A function of a Bourdon tube gage hairspring is a) return the tube to its zero position |
c) eliminate backlash |
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An LP steam pressure gage range shall be between a) 210 and 420 kPa |
a) 210 and 420 kPa |
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An inspectors' test connection a) should be located upstream of a siphon |
e) is not mandatory on LP boilers |
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When installing a siphon it a) must be perpendicular to the piping |
d) should be first filled with water |
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An indication of a pressure gage not performing properly is a) the needle fluctuating |
b) the needle not returning to zero on depressurizing |
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When using a dead weight tester, the effect of friction a) is reduced by rotating the platform |
a) is reduced by rotating the platform |
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The working medium in the dead weight tester is a) air |
d) medium weight oil |
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An essential fitting between the boiler and the a) a check valve |
d) a siphon |
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A steam pressure gauge is graduated in a) pascals |
e) kilopascals |
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The prime importance of boiler fittings are a) economics |
c) safety |
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All boiler fittings not properly or clearly identified should be a) rejected |
a) rejected |
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The purpose of the test connection on a boiler pressure gauge is to a) unplug the siphon tube |
c) install the boiler inspector's pressure gauge |
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As the boiler pressure increases, the bourdon tube of the pressure gauge will a) tend to straighten |
a) tend to straighten |
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The cross-section of a Bourdon tube is generally a) circular |
e) oval |
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An essential fitting between the boiler and the steam pressure gauge is a a) check valve |
d) siphon |
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|
The purpose of the pipe siphon installed between the boiler and the pressure gauge is to prevent a) air from entering the gauge |
c) hot steam from entering the gauge |
|
|
According to the ASME code, the scale on the dial of the steam gauge for a low pressure steam heating boiler shall be graduated to not less than a) 210 kPa |
a) 210 kPa |
|
|
According to the ASME code, the scale on the dial of the a) 210 kPa |
b) 420 kPa |
|
|
An LP steam boiler safety valve shall not be smaller than a) 110 mm |
b) 12.7 mm |
|
|
In order to ensure a safety valve seats properly, it uses a) seat rings |
d) guides and bushings |
|
|
The force of the steam pressure acting on the safety valve disc is a function of a) disc area |
a) disc area |
|
|
The minimum blowdown of an LP safety valve is a) 96% of the set pressure |
c) 14 kPa |
|
|
Popping pressure of an LP safety valve may be adjusted a) any amount |
c) up to 5% |
|
|
The blowdown on a safety valve is adjusted by turning the a) inspector's seal |
d) adjusting ring |
|
|
What does the boiler inspector install to prevent tampering with a) a restraining order |
c) a seal |
|
|
The lip on a safety valve a) allows it to close slowly |
e) allows it to "pop" open |
|
|
A safety valve on a steam heating boiler must not be smaller than a) 25 mm |
d) 13 mm |
|
|
According to the ASME code, steam heating boilers shall have one or more safety valves, adjusted and sealed to discharge at a pressure not exceeding __________ kPa. a) 100 |
d) 103 |
|
|
According to the ASME code, the valve seat diameter of the safety valve on a steam heating boiler must not be smaller than a) 12.7 mm (1/2 in.) |
a) 12.7 mm (1/2 in.) |
|
|
According to the ASME code, the valve seat diameter of the safety valve on a steam heating boiler must not be larger than a) 25.4 mm (1 in.) |
e) 110 mm (4 1/2 in.) |
|
|
For a steam heating boiler, the safety valve shall be such that, with the fuel burning equipment installed and operated at maximum capacity, the pressure cannot rise more than ___________ kPa above the maximum allowable working pressure when all steam outlets are closed. a) 103 |
e) 34 |
|
|
The safety valve shall be installed in __________ position and located in the highest practicable part of the boiler proper. a) the highest |
d) a vertical |
|
|
An LP safety valve lever test should be performed a) weekly |
c) monthly |
|
|
LP boiler safety valves can be repaired a) only when authorized by the inspector |
c) by a qualified boiler operator after permission from the inspector |
|
|
An operator should check that a boiler safety valve will open at its set pressure by a) sending for the inspector to bring his or her test gage |
b) increasing the boiler pressure until the valve opens and noting the pressure on the pressure gage when the valve opened |
|
|
Testing the safety valve by means of the try lever method, is considered good practice when carried out on a a) weekly basis |
b) monthly basis |
|
|
If a safety valve leaks after a try lever test, the operator should a) plug the safety valve outlet |
c) operate the try lever several times to blow away foreign material |
|
|
If you found the safety valve on your heating boiler stuck in the a) tap it gently with a bronze hammer to free it |
d) shut down the boiler and repair or replace the safety valve |
|
|
LP steam boilers must be equipped with a marker indicating the a) maximum water level line |
c) lowest permissible water line |
|
|
A gage glass may be surrounded by a number of thin rods a) when the boiler is a high pressure unit |
d) to protect the glass from damage |
|
|
Quick-closing gage glass valves a) prevent loss of water automatically should glass rupture |
e) require 90 degrees for full travel |
|
|
A disadvantage of a gage glass safety-shutoff valve is a) the glass cannot be blown down |
b) it requires more maintenance |
|
|
Should the steam line or water line to a gage glass become plugged with sludge a) gage glass level will drop in both cases |
d) the gage glass will read high |
|
|
Water column supply line crosses will a) permit piping inspection |
b) allow for piping cleaning and inspection |
|
|
Gage glass rupture may be caused by a) maximum allowable boiler pressure |
b) a cold draft |
|
|
When gage glass nuts are leaking a) the gage glass should be replaced |
d) the glass should be isolated and depressurized before tightening |
|
|
When the water connection between boiler and gage glass becomes plugged, the water level in the glass will show a level after a while, that is a) higher than the level in the boiler |
a) higher than the level in the boiler |
|
|
The lowest visible part of the water gauge glass shall be at least __________ mm above the lowest permissible water level recommended by the manufacturer. a) 25 |
a) 25 |
|
|
The ASME code stamore water gaugtes that each steam boiler shall have one or e glasses attached either directly to the a) 75 |
d) 13 |
|
|
On a multiple steam boiler heating system, a stop valve must be placed at each boiler outlet to a) permit slower system warm-ups |
b) allow boiler isolation from the system |
|
|
Boiler outlet valves are usually a) gate valves because of their low resistance to flow |
a) gate valves because of their low resistance to flow |
|
|
An outside screw and yoke valve a) is always a gate valve |
b) readily shows its operating position |
|
|
The quick closing valves on the water gauge requires only a/an __________ of a turn of the valve spindle to change the valve from the full open to the full closed position and vice versa. a) eighth |
b) quarter |
|
|
The feedwater pipe, before it enters the boiler must be fitted with a __________ valve adjacent to the boiler. a) stop |
d) check |
|
|
A boiler feedwater stop valve a) should never be used to control water level |
e) is used to isolate the feedwater line |
|
|
A globe valve should be used in the feedwater line a) at all times |
b) whenever it may be used for control purposes |
|
|
A stop valve is fitted between the boiler and the feed water check valve a) to regulate the feedwater to the water column |
b) for isolation and to provide a positive shut-off |
|
|
Boiler water foaming may be the result of a) low pH |
d) high TDS |
|
|
Boiler blowdown lines have a specific size range based on a) water impurities |
c) boiler capacity |
|
|
Boiler blowdown piping a) can be reduced in size after the blowdown valves |
b) must be full size to the point of discharge |
|
|
A steam boiler is blown down in order to a) clean the soot and carbon out of the firebox and tubes |
c) discharge sediment and scale forming matter from the boiler |
|
|
The purpose of the small vent valve or cock located on top a) to allow water to escape from the boiler when the boiler is being filled with air |
d) to allow air to escape from the boiler when the boiler is being filled with water |
|
|
A pressure or altitude gage for a hot water boiler a) must be equipped with a siphon |
c) does not require a siphon |
|
|
When a closed expansion tank is used and the system is cold a) the auto fill valve will maintain a system minimum pressure |
a) the auto fill valve will maintain a system minimum pressure |
|
|
An altitude gage on hot water heating boilers is used to indicate a) expansion tank temperature |
d) height of the highest radiator in system |
|
|
Siphon is not required between a pressure or an altitude gauge and a hot water boiler since these boilers are a) filled with steam |
d) filled with water |
|
|
The lever handle of the shut-off cock between a pressure or altitude gauge and a hot water boiler should be __________ to the pipe in which it is located when the cock is open. a) perpendicular |
b) parallel |
|
|
The scale on the dial of a pressure gauge should be graduated a) 1.5 |
a) 1.5 |
|
|
The dial of a pressure gauge on a hot water boiler indicating SI units can be graduated in a) metres of mercury |
e) kPa |
|
|
When the pressure pointer of a closed system reads lower than a) system is full of water |
e) system requires water |
|
|
The temperature indicator of a hot water boiler should indicate water temperature a) at the boiler inlet |
d) at the boiler outlet |
|
|
On a pressure temperature indicator, if the pressure pointer falls below the altitude pointer a) the atmospheric pressure is low |
b) the system is low on water |
|
|
Hot water heating boilers must be equipped with a a) thermometer |
a) thermometer |
|
|
With the fusible plug type of temperature relief device, the fusible plug will melt at __________ degrees Celsius and allow hot water to escape. a) 131 |
e) 99 |
|
|
The expansion and contraction rod type of temperature relief device will open the valve at __________ degrees Celsius and close it at __________ degrees Celsius. a) 99 and 80 |
d) 99 and 71 |
|
|
A boiler pressure relief valve a) shall be installed on the boiler |
b) can be installed anywhere in the system but preferably close to the expansion tank |
|
|
For hot water boilers operating up to 414 kPa, a pressure relief valve opening pressure variation may be as much as a) 14 kPa |
a) 14 kPa |
|
|
A hot water boiler is protected from over pressure by means of a) a safety pop valve |
e) a safety relief valve |
|
|
ASME Section IV, states that each hot water heating boiler shall have at least one officially rated pressure relief valve set to relieve at or __________ the maximum allowable working pressure of the boiler. a) below |
a) below |
|
|
Hot water boilers have stop valves in their inlet and outlet piping a) to allow for better warm-ups |
e) so that the boiler can be drained without draining the system |
|
|
Boiler stop valves shall be a) of the OS&Y type |
c) identified with durable tags |
|
|
During warm-up of a cold hot water boiler excessive pressure build-up is prevented by a) a very slow warm-up |
b) an expansion tank |
|
|
In a closed expansion tank system an air separator a) removes air from the system |
d) directs air into the expansion tank |
|
|
In a hot water heating system, the closed type expansion tank should be a) kept full of water |
c) partly filled with water |
|
|
When a closed type expansion tank on a hot water boiler is completely filled with water and the water in the system is raised in temperature so that it expands, the result will be that a) the boiler expands |
b) the pressure build-up opens the safety relief valve |
|
|
An expansion tank is used to a) store steam |
c) allow for the expansion of the water |
|
|
The head of water in the hot water heating system employing an open type of expansion is referred to the vertical distance from the gauge of the boiler to the level in the __________, which is considered the highest level of the a) steam drum |
d) expansion tank |
|
|
An automatic fill valve a) will maintain maximum system pressure at all times |
c) is not mandatory |
|
|
A closed expansion tank is usually equipped with a) a gage glass |
a) a gage glass |
|
|
Before starting up a new boiler or one that has been out of service the following must be ensured a) the manufacturer's recommendations are read |
b) the boiler has a valid inspection certificate |
|
|
It is very important that boilers should be a) warmed up quickly to prevent condensation |
d) warmed up slowly to prevent thermal shock |
|
|
When cutting in an additional boiler into the heating system a) the stop values in the supply and return lines are both closed |
a) the stop values in the supply and return lines are both closed |
|
|
One of the most important points that should be observed before a new boiler is started and put into continuous operation is to a) check and make sure all valves are opened |
d) make sure the inspection certificate is valid |
|
|
When preparing a boiler for startup and the boiler is equipped with a modulating combustion control, it is best to a) set the manual-auto switch to "auto" |
d) set the manual-auto switch to "manual" and set the flame control switch in the lowest position |
|
|
If the low-water fuel cutoff and/or the high limit control are equipped with a trip-out device on a boiler, it is recommended as part of the startup preparation to a) dismantle the device and check for lose wires |
b) push the reset button to assure that the switches are closed |
|
|
In hot water boiler operation the maximum operating temperature should never exceed a) 77 degrees C |
d) 121 degrees C |
|
|
The pressure relief valve on a hot water heating boiler should be set a) 25% lower than operating pressure |
c) 25% above operating pressure |
|
|
a) poor burner operation |
c) unclean heating surfaces |
|
|
The discharge pressure of steam heating pressure relief valves should never exceed a) 14.7 kPa |
d) 103 kPa |
|
|
How often would you test the low level fuel cut-off on a low pressure steam heating boiler by blowing out the float chamber? a) daily |
a) daily |
|
|
Should any abnormal condition occur during light-off or the temperature building-up period a) continue to run the boiler but reduce the steam and fuel valve settings |
e) shut down the boiler immediately and close the stop valves in the fuel lines |
|
|
There are two conditions that may occur during the warm up period which may seem to be abnormal to the operator but will disappear after the boiler heats up. These conditions are a) uneven expansion and thermal shock |
c) slight smoking and condensation |
|
|
During the warm-up period of a heating boiler the main burner goes out. The operator should a) shut down the boiler immediately, purge the boiler, and restart it. |
b) shut down the boiler, close the fuel valves, and determine the cause of the problem |
|
|
Thermal shock to boilers can be reduced by a) warming up boilers slowly |
e) all of the above |
|
|
The most important rule in safe operation of a steam heating boiler is a) operate the burner properly |
b) keep the water level in the boiler at the proper level |
|
|
To reduce the effects of uneven expansion and thermal shock and to protect a boiler against damage during startup, one of a) always heat up the boiler quickly |
b) always warm up the boiler slowly |
|
|
It is recommended that the differential between the safety relief valve set pressure and the operating pressure of a hot water boiler be kept to a minimum of 69 kPa (10 psi) or __________ % of the relief valve setting. a) 10 |
d) 25 |
|
|
Smoking conditions during the operation of a boiler can be caused by a) improper air/fuel ratio |
a) improper air/fuel ratio |
|
|
Unit heaters differ from convectors in that they use _______ to increase heat transfer. a) metal fins |
c) blowers |
|
|
Convectors use ________ to increase heat transfer. a) metal fins |
a) metal fins |
|
|
In fin coil type heaters, individual room temperature is controlled by a) switches |
c) dampers |
|
|
Unit ventilators use a) only outside air for heating |
d) a mixture of inside and outside air |
|
|
The difference between a convector and a radiator is a) the way they transfer heat |
d) that one is made of cast iron and the other of steel or copper |
|
|
Large areas such as warehouses, are usually heated with a) unit heaters |
a) unit heaters |
|
|
Air can be removed from steam heating systems by a) air vents |
a) air vents |
|
|
A radiator valve is used to control the amount of a) air leaving the radiator |
e) steam entering the radiator |
|
|
A radiator trap is a device that is used to a) allow only air to leave the radiator |
e) allow only water to leave the radiator |
|
|
The vacuum pump performs the following function: a) supplies water to the condensate receiver |
c) returns the condensate (water) back to the boiler |
|
|
The level in the condensate receiver is automatically controlled by a a) float switch |
a) float switch |
|
|
The purpose of a radiator trap is to a) control steam flow into the radiator |
c) drain condensate from the radiator |
|
|
Air vents are used to a) trap excess air |
b) expel the air from heating systems |
|
|
The purpose of a radiator trap is to a) stop the flow of steam |
e) pass condensate and retain steam in the radiator |
|
|
The piping and heating units of a steam heating system must be so arranged that a) the condensate can flow freely to the heating units |
c) steam can flow freely to all heating units |
|
|
In a gravity return system the boiler should be placed a) well above the highest radiator |
b) well below the lowest radiator |
|
|
The Hartford Loop prevents the water in the boiler from a) exceeding the maximum temperature |
c) dropping below a safe level |
|
|
All supply and drain lines of a steam heating system must be pitched to a) allow for drainage of condensate |
a) allow for drainage of condensate |
|
|
When starting up a steam heating boiler it should be filled to a) the maximum level |
c) 1/2 of a gage glass |
|
|
If the water level falls too low during operation of a steam heating boiler the operator should a) tell his or her supervisor |
d) shut the boiler down |
|
|
In the case of radiators and convectors, the main sources of trouble are the a) air vents |
e) valves and traps |
|
|
Finned convectors should be kept free of a) air |
e) all of the above |
|
|
Slow or insufficient heat throughout a building heated by steam can be caused by a) too high a firing rate |
b) too low a firing rate |
|
|
Slow or insufficient heat in one or more rooms in a steam heated building can be caused by a a) faulty steam trap |
a) faulty steam trap |
|
|
The maximum temperature of water in a gravity hot water system is a) 65 degrees C |
c) 77 degrees C |
|
|
In a forced circulation system the expansion tank a) a vacuum |
b) a pressure well above atmospheric pressure |
|
|
A forced hot water circulating system can be classified as the following type: a) loop system |
e) all of the above |
|
|
In a one pipe hot water system the fitting that directs the water to each converter is called the a) diverter |
a) diverter |
|
|
In a radiant heating system the maximum surface temperature is a) 10 degrees C |
c) 30 degrees C |
|
|
In radiant heating system changes are a) difficult to make |
a) difficult to make |
|
|
Automatic snow melting systems can use a) hot water and antifreeze mixed |
e) all of the above |
|
|
Snow melting systems are usually filled with a) water only |
c) ethylene glycol and water |
|
|
Advantages of the forced circulation hot water heating systems are a) reduction in pipe size and greater heat storage capacity |
a) reduction in pipe size and greater heat storage capacity |
|
|
A hot water boiler of the same output is a) larger than a steam boiler |
b) smaller than a steam boiler |
|
|
In a hot water system compared to a steam heating system, if there is a leak damage will a) be greater in the steam system |
b) be greater in the hot water system |
|
|
Which of the following use a boiler in the system? 1. steam heating a) 1, 2 |
e) 1, 3, 4 |
|
|
Diverter fittings are used in the supply lines to heating units a) to compensate for a low heating load |
b) when a higher heating output is required from the heating unit |
|
|
An air separator should always be installed in a) a horizontal pipe |
a) a horizontal pipe |
|
|
The air removed by the air separator is vented to the a) air space at the top of the boiler |
d) expansion tank |
|
|
To ensure that each zone circuit has the proper flow of water to provide the required heat a: a) flow control valve is used |
e) balancing valve is used |
|
|
The temperature control on a steam to hot water converter, controls a) the pump speed |
d) the steam control valve |
|
|
Excessive pressure build-up due to a rise in temperature and the resulting expansion of the water in the system is prevented by the use of a) a float tank |
c) an expansion tank |
|
|
To prevent corrosion in the expansion tank it is sometimes filled with a) nitrogen |
a) nitrogen |
|
|
Improper location of the circulating pump and expansion tank can cause a) the circulating pump to cavitate |
e) all of the above |
|
|
The expansion tank is normally attached to the a) boiler or the hot water supply line near the boiler |
a) boiler or the hot water supply line near the boiler |
|
|
The minimum reading on an altitude gage of a boiler in a large plant is from the top of the boiler to the highest point in the system plus a) 0.6 m |
d) 1.2 m |
|
|
The purpose of a pressure reducing valve is to a) level out the flow of steam or hot water |
b) automatically reduce pressure and maintain it |
|
|
What type of boiler would you expect to find in a hot water system, incorporating a converter? a) hot water boiler |
b) steam boiler |
|
|
In a warm air heating system the cold air return registers are located a) in exterior walls |
b) in interior locations |
|
|
The major disadvantage of an electric resistance coil furnace for warm air heating is a) the high cost of electricity |
a) the high cost of electricity |
|
|
Lowboy furnaces are just over a) 1.0 m in height |
e) 1.2 m in height |
|
|
The advantage of having duct furnaces instead of a large central furnace is a) less initial cost |
c) better control of heat in each zone of the building |
|
|
The power supply for an electric resistance coil furnace is a) 60 V |
c) 240 V |
|
|
In a fin-coil heat exchanger the primary source of heat for the exchanger is a) steam or hot water |
a) steam or hot water |
|
|
A type of directly fired space heater is a) a unit heater |
d) all of the above |
|
|
High efficiency furnaces and heaters range in annual fuel utilization efficiency (AFUE) from a) 94 - 98% |
b) 80 - 95% |
|
|
In high efficiency furnaces if the temperature of the flue gas drops below 65 degrees C the a) flue gas will condense |
b) water vapour will condense |
|
|
In a pulse combination furnace the stated efficiency is a) 94 - 98% |
a) 94 - 98% |
|
|
Heat exchangers in gas fired furnaces are made of a) brass |
d) steel |
|
|
Air filters can be divided into two groups a) mechanical and rotating drum |
e) mechanical and electronic |
|
|
Electronic filters will remove a) all particles from the air |
b) fine particles from the air |
|
|
The perimeter loop system of furnace ducting is ideal for a building with a) no insulation in the walls |
c) no basement |
|
|
Which of the following is a type of outlet in a warm air heating system? a) a grill |
e) all of the above |
|
|
Supply outlets should always be located a) in walls |
d) to best prevent cold drafts |
|
|
In a warm air heating system, the heated air should enter the rooms preferably via the a) high wall registers on the inside wall |
c) baseboard registers on the outside wall |
|
|
Sleeve bearings on furnace fans require a) no lubrication |
c) a few drops of oil every six months |
|
|
Furnace heat exchangers should be checked for corrosion because a) carbon monoxide could leak into the building |
a) carbon monoxide could leak into the building |
|
|
Insufficient heat throughout a building is likely caused by a) too high an air flow |
b) insufficient heat input |
|
|
Actual ventilation rates may vary per person from a) 0.5 to 0.6 cubic metres/min |
d) 0.14 to 1.5 cubic metres/min |
|
|
Ventilation can be divided into two basic methods: a) forced and natural |
b) mechanical and natural |
|
|
Natural ventilation is improved by the use of a roof a) ventilator |
a) ventilator |
|
|
Mechanical ventilation can be divided into which types? a) natural air intake, natural exhaust |
b) mechanical air intake, natural exhaust |
|
|
In a mechanical air intake, natural exhaust ventilation system the pressure in the building is a) well below atmospheric pressure |
d) slightly above atmospheric pressure |
|
|
Living organisms that must be removed from the air are a) insects and pollen |
c) bacteria and spores |
|
|
Mechanical filters can be divided into two broad classes: a) wet and dry |
e) throwaway and renewable |
|
|
Viscous filters are highly efficient in the removal of a) fine dust, fumes, and smoke |
d) dust and pollen |
|
|
Electrostatic filters are highly efficient in the removal of a) dust and pollen |
b) fine dust, smoke, and fumes |
|
|
Ultraviolet light is used to remove __________ from the air. a) dust and pollen |
c) bacteria and spores |
|
|
Infrared radiant energy is directed towards a) ceilings |
d) floors |
|
|
Infrared heaters are usually mounted a) overhead |
a) overhead |
|
|
Gas-fired infrared heaters use the principle of a) heating a gas |
b) heating a solid surface |
|
|
In an internally fired, gas fired infrared heater, the surface temperature is about a) 300 degrees C |
b) 400 degrees C |
|
|
A low temperature catalytic heater contains a layer of a) metal impregnated with a catalyst |
d) glass wool impregnated with a catalyst |
|
|
The quartz lamp heating element will respond a) instantaneously |
b) in a few seconds |
|
|
The main disadvantage of electric heating is the a) high maintenance cost |
d) high operating cost |
|
|
In an open wire type heating element the resistance wire is a) tungsten |
e) nickel-chromium |
|
|
Electrical heating can be divided into two general groups: a) floor and wall |
b) direct and indirect |
|
|
In an electric snow melting unit, a thermostat should be used to automatically shut the system down when the outdoor a) 0 degrees C |
c) 2 degrees C |
|
|
The basic types of heating systems are: 1. steam heating a) 1, 2, 4 |
d) 1, 2, 3, 4 |
|
|
A prime mover is a) an electric motor |
b) a steam turbine |
|
|
Large power production plants tend to be of the thermal type because they can burn solid fuels and: a) they are the least expensive to build |
c) the heat cycle they use is the most efficient |
|
|
Whenever feasibly possible, when checking bearings on running pieces of equipment it is wise to a) check the oil quality leaving each |
c) get accustomed to normal running temperature and vibration by feel |
|
|
One of the first ways to detect a fault in a reciprocating engine is a) by sound |
a) by sound |
|
|
A steam turbine's exhaust can often supply a process with steam because a) processes always require a lower steam pressure |
d) it is free of oil |
|
|
The exhaust steam from a steam turbine is more acceptable for process than the exhaust from a steam engine because a) it is much hotter |
c) it is free of oil |
|
|
Turbines often have segmental carbon ring sealing glands which are held in place by a) labyrinths |
d) garter springs |
|
|
A steam turbine should trip or shut down when normal operating speed is exceeded by a) 250 RPM |
d) 10 to 15% |
|
|
Condensing turbines a) are always impulse turbines |
b) will have a vacuum in the last row of rotating blades |
|
|
Which turbine uses a condenser? a) back pressure turbine |
b) a turbine exhausting to a vacuum |
|
|
The shrouding installed on the blading of a steam turbine serves to: a) cool the blade tips |
e) confine the steam to the blades |
|
|
The turbine overspeed trip: 1. prevents the turbine from vibrating a) 2, 4, 5 |
a) 2, 4, 5 |
|
|
The overspeed trip of a steam turbine a) operates on turbine vibrations due to high speed |
b) is installed on all turbines |
|
|
Turbine overspeed trip a) prevents the turbine from vibrating |
b) will close the steam stop valve to the turbine |
|
|
Turbine lubricating oil a) is not required for small impulse turbines |
d) can be used to operate the turbine governor |
|
|
The purpose of turbine glands is to prevent a) water from entering the turbine |
c) steam escaping from the turbine |
|
|
Shaft sealing in high output turbines is done with a) water seals |
e) labyrinth seals |
|
|
When the steam pressure drop occurs in only the stationary members or components of a turbine, the turbine is known as a) a single stage unit |
b) an impulse unit |
|
|
A large reaction turbine will have a) no thrust bearings |
e) steam pressure dropping through moving and stationary sections |
|
|
Turbine speed can be "fine tuned" with a device which will be limited to about 10% over the rated speed. This device is the a) governor valve |
d) hand speed control |
|
|
Turbine thrust bearings are fixed to the casing and prevent axial movement of the spindle by contacting a component on the shaft known as a a) shaft sleeve |
c) collar |
|
|
Shaft sealing carbon glands are a) lubricated by the main oil pump |
d) self-lubricating |
|
|
The great majority of steam turbine governing systems utilize the a) hydraulic system principle |
c) mechanical centrifugal principle |
|
|
Reaction turbines a) have bucket shaped blades |
b) have a pressure drop through the moving and stationary blades |
|
|
Reaction turbines a) have all of the steam pressure drop take place in the stationary nozzle |
b) have a velocity increase in the fixed blading |
|
|
In an impulse turbine a) the steam flow is reduced through the nozzles |
b) the steam pressure is reduced in the nozzles |
|
|
The steam turbine that has a pressure drop across every set of blades is the __________ turbine. a) double-stage impulse |
e) reaction |
|
|
When starting a steam turbine it is customary practice to a) analyze the oil for water prior to rolling |
d) test the overspeed trip as soon as running speed is attained |
|
|
The average amount of water volume which evaporates from a cooling tower is a) 2% |
d) 5% |
|
|
Natural draft cooling towers operate most effectively in large open spaces and a) where wind is relatively constant |
a) where wind is relatively constant |
|
|
Excessive wind velocity in a natural draft cooling tower may cause a) louvers to become broken |
b) high water drift or losses |
|
|
Compared to a crossflow tower, a counterflow tower a) is not as tall |
c) requires less floor space |
|
|
Water contained in the airstream at the discharge of a cooling tower is removed a) with centrifugal separators |
e) with drift eliminators |
|
|
A cooling tower which requires neither fan nor fill is the a) natural draft unit |
c) venturi unit |
|
|
A valve which prevents water flow over the fill of a tower during cold weather should not be closed until the temperature reaches a) - 0.5 degrees C |
e) + 27 degrees C |
|
|
To prevent cooling tower basin water from freezing during cold weather many units are equipped with a) ethylene glycol antifreeze systems |
b) electric basin heaters |
|
|
You are replacing the cooling tower fan motor bearings because a) the motor was running single phase |
d) the rotor was rubbing the stator |
|
|
Scaling is not as severe in towers when compared to boilers because a) tower water does not evaporate |
d) temperatures are not as high |
|
|
A gas turbine compressor is usually a) centrifugal type |
c) dynamic axial design |
|
|
The compressor on the gas turbine a) can be driven by the load turbine |
a) can be driven by the load turbine |
|
|
The combustion chamber of a gas turbine a) increases the pressure of the compressed air |
c) burns fuel with excess air |
|
|
Many typical steam plant auxiliaries are eliminated with a gas turbine due to its a) small size |
d) simplicity |
|
|
Gas turbines are very popular where a) noise does not present a problem |
b) water is scarce |
|
|
Gas turbines are ideal when considering a) long warm-up periods |
b) emergency power generation |
|
|
A two shaft gas turbine a) has the load turbine downstream from the compressor turbine |
a) has the load turbine downstream from the compressor turbine |
|
|
A gas turbine is not self-starting. It must be rotated at __________ of its maximum speed before fuel is turned on. a) 10% to 30% |
c) 20% to 30% |
|
|
Early gas turbines were handicapped by a) metal not being able to withstand high speed centrifugal forces |
c) metals not standing the high temperatures involved |
|
|
The output power of a gas turbine is directly related to the a) mass of gas passing through the turbine per second |
a) mass of gas passing through the turbine per second |
|
|
The low installation cost of a gas turbine is a) due to cheap materials in the blades |
e) because less auxiliary equipment is needed |
|
|
Some of the characteristics which make the gas turbine a better choice over other prime movers are: 1. low maintenance a) 1, 2, 3, 4 |
c) 1, 2, 4 |
|
|
The air side of a gas turbine regenerator is located a) before the compressor |
e) downstream of the compressor |
|
|
A gas turbine performs most effectively if a) lube oil is of the proper viscosity |
d) ambient air temperature is low |
|
|
A combined steam and gas turbine arrangement can be termed a) an ideal system |
b) a cogeneration system |
|
|
The purpose of a regenerator is a) to clean the exhaust gases |
b) to improve the efficiency of the turbine |
|
|
In a compression ignition engine the fuel is ignited by a) an electric spark |
b) the compressed air temperature |
|
|
Diesel engine governing is accomplished by a) varying the fuel quality |
c) varying the fuel quantity |
|
|
The fuel for a diesel engine is a) light fuel oil |
c) mechanically atomized by high pressure |
|
|
Four-stroke cycle engine valves are a) operated by cams |
a) operated by cams |
|
|
An engine which develops one power stroke with every other turn of the crankshaft is the a) two stroke diesel engine |
c) four stroke natural gas engine |
|
|
Four cycle engine lubrication is usually a) forced by pump |
a) forced by pump |
|
|
An example of an engine which gives high torque at low speeds would be that of a a) chain saw |
c) four stroke motocross motorcycle |
|
|
A two cycle engine a) must always have lube oil premixed with the fuel |
d) "pops" twice as often as an equivalent cylinder four stroke engine |
|
|
Pre-mixing lube oil and fuel or having a special lube oil injection system is typical of the average a) snowmobile engine |
a) snowmobile engine |
|
|
A major difficulty encountered with a two-stroke cycle engine is a) the high torque at low speeds |
e) exhausting the spent gases from the cylinder |
|
|
A two cycle gasoline engine a) has more moving parts than a four cycle |
e) is of more simple construction than a four cycle |
|
|
Cylinder scavenging a) is more efficient in a 2 cycle engine than a 4 cycle type |
c) is the removal of exhaust gases from the cylinder |
|
|
The purpose of a spark plug is a) to ignite the fuel air mixture in a gasoline engine |
a) to ignite the fuel air mixture in a gasoline engine |
|
|
Compression ignition engines a) need suction end discharge valves |
b) will compress air only on the compression stroke |
|
|
The injection pump of a diesel engine is driven by a) piston action |
e) the camshaft |
|
|
Ignition in a diesel engine is started by a) a glow plug |
d) compression in the cylinder |
|
|
Using a compressed air starting motor is a popular method of starting a a) large stationary diesel engine |
a) large stationary diesel engine |
|
|
When using compressed air to each cylinder for starting purposes, the pressure is approximately a) 520 kPa |
d) 2,100 kPa |
|
|
Reduction in sealing qualities between the piston rings and cylinder wall by the lube oil may be the result of a) low cooling water temperature |
c) high cooling water temperature |
|
|
The temperature to which the air can be raised at the turbine inlet is a) an indication of a unit's power |
d) an indication of the unit's efficiency |
|
|
A pump is capable of suction lift due to a) its ability to convert kinetic energy into potential energy |
e) atmospheric pressure |
|
|
Centrifugal pumps do not develop good suction lift because a) atmospheric pressure is usually too low |
c) their internal component clearances are too high |
|
|
It is generally accurate to say that a) 9.8 kPa pressure results from every metre of water depth or height |
a) 9.8 kPa pressure results from every metre of water depth or height |
|
|
Preferably, dynamic pumps should be located a) directly under the liquid source when suction lift is involved |
e) below the liquid source when suction head is involved |
|
|
The vertical distance from the liquid surface up to the pump centre-line plus the vertical distance from the pump centre-line up to the surface of the liquid in the discharge tank is a) static discharge head |
e) total static head |
|
|
The difference between static suction head and static discharge head is a) total static head |
a) total static head |
|
|
When a pump discharges into a vessel operating at 300 kPa, the 300 kPa is referred to as a) dynamic head |
b) equivalent head |
|
|
The total static head of a pump a) is the capacity of the pump |
b) is the difference between the static suction head and the static discharge head |
|
|
When a reciprocating pump discharges while its piston or plunger moves in only one direction, it is termed a a) positive displacement unit |
b) single acting unit |
|
|
Centrifugal pumps convert rotating mechanical energy into kinetic energy then a) discharge the kinetic energy |
d) into potential energy in the form of pressure |
|
|
A hot water heating system circulator should a) be directly coupled |
c) be very quiet in operation |
|
|
The capacity of a centrifugal pump a) varies with discharge pressure |
a) varies with discharge pressure |
|
|
Centrifugal pump power requirements are decreased when a) discharge pressure is decreased |
b) the litres moved per minute is decreased |
|
|
A rotary pump a) is a variety of dynamic unit |
c) should be equipped with a relief valve |
|
|
When starting-up a rotary pump you must be sure that the a) discharge valve is closed |
b) discharge valve is open |
|
|
Rotary pumps: 1. are high pressure pumps a) 1, 2 |
c) 1, 4 |
|
|
A double-acting pump a) has two pistons on the pump end |
e) is a positive displacement pump |
|
|
A volute type pump a) is a positive displacement pump |
b) has a progressively expanding spiral casing |
|
|
A diffuser pump: 1. has stationary guide vanes surrounding the impeller a) 1 |
d) 1, 2 |
|
|
Turbine pumps: 1. are high capacity pumps a) 1 |
c) 2, 3 |
|
|
A centrifugal pump consists of a) an impeller surrounded by a casing |
a) an impeller surrounded by a casing |
|
|
The capacity of a centrifugal pump should only be reduced by a) throttling the suction valve |
e) closing in the discharge valve |
|
|
Cavitation of a pump refers to, when: a) the pump is filled with air |
b) the pump is filled with vapour |
|
|
Rotary pumps: 1. have tight clearances on all moving parts a) 1 |
d) 1, 3, 4 |
|
|
If a pump is cavitating what can you do to prevent or reduce the cavitation? a) close the casing vent valve |
e) raise the suction pressure |
|
|
A positive displacement stand by-pump will have a) the vent and drain valves open |
d) the suction valve open and the discharge valve open |
|
|
Pumps handling cryogenic materials operate a) as staged units |
b) at extremely low temperatures |
|
|
A circulating pump is usually a) connected with some type of heat exchanger system |
a) connected with some type of heat exchanger system |
|
|
A multi-stage pump would be used a) when the lift is great |
c) when the head is great |
|
|
Turbine pumps are best suited for a) low capacity low pressure service |
b) low capacity high pressure service |
|
|
Pump wear rings are installed on an impeller by set screws, threading or a) shrinking |
a) shrinking |
|
|
Wear rings are usually constructed of a) ceramics or aluminum |
c) bronze or cast iron |
|
|
Wearing rings: 1. are used on impellers a) 1, 2, 3 |
b) 1, 2, 4 |
|
|
A stuffing box: 1. stops air leaking into the casing when the pressure is a) 1, 3 |
e) 1, 2, 4 |
|
|
Mechanical seals: 1. are used where leakage is objectionable a) 1, 2 |
b) 1, 2, 3 |
|
|
Compression type packing: 1. prevents air from entering the pump a) 1 |
d) 1, 2 |
|
|
Lantern rings: 1. prevent liquid leakage from the pump a) 1, 2, 3 |
c) 2, 3, 4 |
|
|
The seal cage on the shaft of a centrifugal pump a) holds the shaft packing against the shoulder of the stuffing box |
c) distributes sealing water to the packing |
|
|
The main advantage of a pump using a mechanical seal is a) lower first cost |
b) less maintenance |
|
|
A slight leakage is desired between the pump shaft and packing of the majority of pumps in order to a) prevent the ingress of atmospheric air |
d) lubricate the surfaces |
|
|
If a stuffing box is to prevent the ingress of air, it is equipped with a) a vacuum breaker |
b) a seal cage |
|
|
Any leakage occurring through the surfaces of a mechanical seal will a) not be visible to the operator |
e) be radial to the shaft |
|
|
The component of a mechanical seal which prevents axial leakage is a) the seal ring |
d) the O-ring |
|
|
What size of packing should you use, to repack a pump gland having the a) .5 cm |
e) .95 cm |
|
|
New pump packing should be installed a) tight enough to stop leakage |
b) loose enough to allow leakage for lubrication |
|
|
Flexible couplings will compensate for a) overheating of packing |
b) axial shaft misalignment |
|
|
Shaft misalignment during operation of a pump can be caused by bearing wear, thermal expansion, and a) shaft flexing |
a) shaft flexing |
|
|
Proper priming and venting of a pump is important, especially if a) the medium being pumped is high temperature |
d) a mechanical seal is used |
|
|
Priming of a centrifugal pump refers to a) removal of water from pump |
b) filling the pump casing with liquid and removing the air |
|
|
Priming a water pump means a) raising the suction line to the level of the water |
d) filling the pumps casing and suction line with water |
|
|
If the packing gland of a centrifugal water pump is leaking too a) tighten up the gland until all leakage has been stopped |
b) tighten up the gland but permit a slight amount of leakage |
|
|
When lubricating equipment, the operator should also check for: 1. unusual machine noises a) 1, 2, 3 |
e) 1, 2, 3, 4 |
|
|
Most pump failures, damage, or both occurs a) after about six months of continuous service |
c) during initial start-up |
|
|
When a pump is operating, your inspection should include the following: a) you must check the impeller |
c) you should check the discharge pressure |
|
|
A plugged impeller symptom or result will be a) air leaks in suction line and stuffing boxes |
e) no liquid being delivered |
|
|
If pump speed is too high a) the driver may be overloaded |
a) the driver may be overloaded |
|
|
If a pump is running and has no discharge pressure, what will a) close the suction valve a little |
d) check to see if the suction valve is open |
|
|
You discover that your feed water pump is not delivering sufficient water. A possible cause is a) the impeller is plugged |
a) the impeller is plugged |
|
|
Compressed air machinery would most likely be used in a) coal mines |
a) coal mines |
|
|
Compressed air tools tend to be a) heavier than equivalent electrical tools |
d) more expensive than electrical tools |
|
|
In a centrifugal compressor the kinetic energy is converted to potential energy in the a) volute, diffuser, or both |
a) volute, diffuser, or both |
|
|
The compressor which would favour volume over pressure would be the a) rotary lobe |
d) centrifugal |
|
|
Positive displacement air compressor types are a) centrifugal compressors |
b) gear compressors |
|
|
Single stage reciprocating air compressors a) must have an air receiver |
d) could have two cylinders |
|
|
A belt driven lubricator is very popular on a a) reciprocating double acting unit |
e) sliding vane unit |
|
|
Higher gearing is commonly used on a) rotary lobe units |
b) screw units |
|
|
Relative to a dry-pipe fire system, an automatic air supply shall be connected so that proper pressure can be maintained in each system, is a statement of the a) National Fire Protection Association Code |
a) National Fire Protection Association Code |
|
|
In order to protect the driver, a start-stop air compressor a) an intercooler |
d) pre-start automatic unloading |
|
|
The valves on a reciprocating compressor are opened by a) a pressure difference |
a) a pressure difference |
|
|
Compressor unloaders a) could close the discharge valve |
c) could keep the suction valve open |
|
|
Where pistons move in a cylinder it is necessary a) tension |
b) sealing |
|
|
An air compressor which gives two compression strokes per a) multistaged two cylinder |
c) single cylinder double acting |
|
|
To reduce air temperature between stages, we would use a) an intercooler |
a) an intercooler |
|
|
An air receiver used in an air compression, system will perform the following functions: 1. act as a storage vessel a) 1, 2 |
b) 1, 2, 3 |
|
|
An air compressor auxiliary which will decrease the power requirement is the a) receiver |
c) intercooler |
|
|
Intercoolers should be equipped with a) moisture separators |
b) safety valves |
|
|
Intercoolers a) cool the air in the cylinders |
c) should have a safety valve |
|
|
Intercoolers a) must have a drain |
a) must have a drain |
|
|
Air receivers a) must have a gage glass |
d) must have a safety valve |
|
|
Relative to lubrication, one place where wear is beneficial is a) new babbit bearing surfaces which wear smooth |
a) new babbit bearing surfaces which wear smooth |
|
|
The intermeshing of gear teeth is a place where lubrication a) corrosion reduction is very important |
d) shock absorption is very important |
|
|
The lubricant performs a number of functions. Indicate which of the following are the most important: 1. reduce wear a) 1, 2 |
d) 1, 4 |
|
|
A material which is commonly used as a solid lubricant is a) tallow |
d) molybdenum disulphide |
|
|
Grease is not a suitable lubricant a) if the atmosphere contains a lot of moisture |
e) if a large amount of cooling is desired |
|
|
A semi-solid lubricant: a) can only be used for high temperature services |
c) is less likely to drip or splash from bearings |
|
|
Lubricant for an anti-friction bearing is a) mineral oil |
e) barium and lithium base grease |
|
|
Which type of grease is the cheapest and most commonly used? a) lithium base |
d) calcium base |
|
|
The property of an oil which indicates its ability to support a load is a) viscosity |
a) viscosity |
|
|
If an oil's viscosity changes much with little temperature change then it will have a a) low viscosity index |
a) low viscosity index |
|
|
Which of the following has the greatest effect on a) pressure |
d) temperature |
|
|
The resistance of a liquid to internal deformation a) pour point |
d) viscosity |
|
|
Which type of oil produces higher fluid friction? a) a high viscosity oil |
a) a high viscosity oil |
|
|
Oil additives a) should not affect all other characteristics greatly |
a) should not affect all other characteristics greatly |
|
|
If you desire an oil to flow at a much lower temperature you would most likely add a) a viscosity index improver |
b) pour point depressants |
|
|
High capacity steam turbine oils should a) have a low specific heat |
c) be fire resistant |
|
|
Air compressor oil should a) have a very low viscosity |
b) have low carbon residue |
|
|
High viscosity oils are normally used for the following applications: a) low speed, high load |
a) low speed, high load |
|
|
A lubricant characteristic which will indicate its ability to support a heavy load at low speed is a) viscosity index |
c) viscosity |
|
|
A form of lubrication which requires continual motion of a shaft or surface is a) boundary lubrication |
e) fluid film lubrication |
|
|
Fluid film lubrication a) is used for heavy loads |
a) is used for heavy loads |
|
|
Fluid film lubrication a) is always used with a high viscosity oil |
b) is also called flood lubrication |
|
|
In a forced lubrication system, a pump supplies oil _________________ for the bearings. a) by gravity |
e) under pressure |
|
|
Large journal or sleeve bearings have grooves a) in the high pressure area of the bearing babbit |
d) in the non-pressure area |
|
|
A large journal bearing which is running hotter than normal can be cooled by a) direct application of cool water |
b) loosening the bearing caps |
|
|
A thrust bearing which does not utilize the oil wedge principle of lubrication is the a) Michell type |
b) collar type |
|
|
One of the main functions of the lubricant in a sealed, grease type antifriction bearing is a) wear reduction |
b) sealing |
|
|
A journal bearing a) controls thrust movement |
e) supports a shaft |
|
|
Thrust bearings: 1. are used on reaction turbines a) 1, 2, 4 |
a) 1, 2, 4 |
|
|
The lubricant for an anti-friction bearing a) will separate the moving parts completely |
c) could be a semi-solid lubricant |
|
|
A collar thrust bearing: 1. can support more load than a Michell thrust bearing a) 1, 2 |
b) 2, 3 |
|
|
An anti-friction bearing a) could be a thrust bearing |
a) could be a thrust bearing |
|
|
A collar thrust bearing a) must have a shiny surface |
e) has boundary lubrication |
|
|
A type of anti-friction bearing is the __________ bearing. a) spiral |
c) ball |
|
|
Using pressurized air to blow out a cleaned bearing a) should only be done when ventilation is maximum |
c) will cause the bearing to become "pitted" |
|
|
When replacing or removing an antifriction ball bearing, the applied force should a) not be transmitted through the bearing balls |
a) not be transmitted through the bearing balls |
|
|
Applying installation forces through the balls of a bearing a) bearing misalignment |
e) brinelling |
|
|
A normal antifriction bearing temperature operating range is a) 150 to 160 degrees C |
d) 65 to 70 degrees C |
|
|
When grease is used in an antifriction bearing, the bearing housing should not be filled more than __________ full. a) 1/4 |
b) 1/3 |
|
|
Causes of anti-friction bearing failures are: 1. improper fitting a) 1, 3, 4 |
d) 1, 2, 3, 4 |
|
|
In an atom the electrons a) orbit around each other |
c) are attracted to the protons |
|
|
When a number of electrons pass a given point over a specific time period the energy may be referred to as a) an ampere |
a) an ampere |
|
|
A basic law of electricity is, unlike charges attract each other and like charges a) repel each other |
a) repel each other |
|
|
The flow of electrons in a uniform direction is called a) voltage drop |
b) electrical current flow |
|
|
Since the discovery of electrons, it has been determined that a) positive to negative |
c) negative to positive |
|
|
An open circuit is one in which a) a switch is closed |
d) a switch is open |
|
|
A triple pole single throw switch is one a) which opens and closes three wires of an electric circuit |
a) which opens and closes three wires of an electric circuit |
|
|
The purpose of having an upward movement of a switch handle to close the switch is a) to have the handle out of the way |
e) to prevent the switch from closing due to gravity |
|
|
The battery of an electrical circuit a) gives a load to the circuit |
c) supplies electromotive force |
|
|
The unit of measure for electrical current flow is the a) Ohm |
d) Ampere |
|
|
Atoms that have greater numbers of electrons in the outer shell a) positively charged |
e) not good conductors |
|
|
Electrons are negatively charged particles a) flowing through the atoms centre |
b) orbiting about the nucleus of an atom |
|
|
_____________ current flow is from positive to negative. a) Reversed |
d) Conventional |
|
|
If an electrical ___________________ is placed across a conductor, the electrons will drift from the negative end towards the positive end of the conductor, assuming the electron theory. a) potential |
a) potential |
|
|
A material that conducts electrical current is called a) a volt |
b) a conductor |
|
|
The electrical pressure that causes current flow through a circuit is a) electromotive force |
a) electromotive force |
|
|
The flow of electrons in a uniform direction from atom to atom through a circuit, is known as a) electromotive force |
d) current |
|
|
An insulator is material that will not _________________ an electrical current. a) reduce |
e) conduct |
|
|
A closed electrical circuit will a) not allow current to flow |
e) allow current to flow |
|
|
An electrical device which is designed to start and stop current flow is the a) potentiometer |
d) switch |
|
|
Ohms Law can be stated as a) E = IR |
a) E = IR |
|
|
The voltage drop across a 20 ohm resistor with 10 amps flowing would be a) 2 |
c) 200 |
|
|
In an equivalent circuit developed from a multi-resistor series circuit a) the resistance will be the reciprocal sum of the original resistances |
c) the sum of voltage drops across the original resistances will be equal to the voltage drop of the equivalent circuit |
|
|
Three resistances of 20, 50 and 80 ohms make up a series circuit. Supply voltage is 400. The current flowing would be a) 2.67 amps |
a) 2.67 amps |
|
|
Equivalent resistance is decreased a) when voltage is decreased |
b) when a circuit is in parallel |
|
|
Three resistors of 20, 60 and 120 ohms are connected in parallel and the circuit amperage is 60. The applied voltage would be a) 7,200 |
c) 800 |
|
|
The unit for opposition to current flow is the a) volt |
c) ohm |
|
|
The voltage required to force a current of 15 amps through a resistance of 5 ohms would be a) .33 volts |
e) 75 volts |
|
|
Current flow is a) proportional to the applied voltage |
a) proportional to the applied voltage |
|
|
When one ampere of current flows through a resistance by the application of one volt the resistance will be a) one watt |
b) one ohm |
|
|
Current flow is inversely proportional to the a) voltage |
c) resistance |
|
|
The value of the current flow in an electric circuit, where the voltage is 12 volts and the resistance is 3 ohms is a) 4 watts |
d) 4 amperes |
|
|
The total resistance of three resistances in a series circuit can be given as a) R1 + R2 + R3 |
a) R1 + R2 + R3 |
|
|
The equivalent resistance of three resistances 10 ohms, 25 ohms and 50 ohms connected in parallel is a) .16 ohms |
b) 6.25 ohms |
|
|
A conductor's resistance is a) directly proportional to its cross-sectional area |
c) inversely proportional to its cross-sectional area |
|
|
Most conductors tend to a) increase in resistance with increase in temperature |
a) increase in resistance with increase in temperature |
|
|
Voltage is a) the rate of current flow |
c) electromotive force |
|
|
Electromotive force a) is capable of moving a quantity of electrons at some rate per period of time |
a) is capable of moving a quantity of electrons at some rate per period of time |
|
|
An ampere is the _______________ of current flow. a) cause |
c) measurement |
|
|
_______________________ is an electromotive force. a) Amperage |
e) The volt |
|
|
Under normal circumstances, the heat produced by the electrical wires of a circuit is very small due to the a) large diameter of the conductor |
b) low resistance of the conductor |
|
|
The force required to produce a current of one ampere through a) one watt |
c) one volt |
|
|
The unit of current flow is the a) watt |
b) ampere |
|
|
The opposition a device or material offers to the flow of electric current, is known as: a) a resistance |
a) a resistance |
|
|
An electric motor is designed for a current of 30 amperes with an applied voltage of 220 volts. a) calculate the power consumed b) calculate the efficiency of the motor if the rated output is 6.27 kW Answers: a) = __________________ watts b) = __________________ % |
a) 6600 Watts b) 95%
|
|
|
What power is dissipated by a resistor with a supply voltage of 120 volts and current of 8 amperes? a) 960 ohms |
d) 960 watts |
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Electrical power can be determined by the formula a) P = IE |
a) P = IE |
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The basic unit of mechanical or electric power is the a) volt |
b) watt |
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The voltage required to be supplied to a 12 kW motor drawing 24 amperes is a) 5 kilovolts |
e) 500 volts |
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If the power dissipated by a resistor is 1.2 kW when supplied with a) 91.666 amperes |
d) 10.909 amperes |
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Neglecting the efficiency of a 15 kW motor connected to a 400 volt supply, the amperage will be a) 26.667 amperes |
b) 37.5 amperes |
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The watt is an electrical unit of measure for a) resistance |
d) power |
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The basic unit of electrical power is the watt, which is the result of a) volts plus amperes |
c) volts times amperes |
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Magnetic flux can be said to be a) lines of force within a magnet and flowing N to S |
b) lines of force outside a magnet and flowing N to S |
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Current flow direction and intensity will a) affect magnetic field direction and intensity |
a) affect magnetic field direction and intensity |
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When a material or substance does not form a magnetic flux easily it is said to have a) permeability |
c) reluctance |
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The space or zone around a magnet through which lines of force travel is termed a) magnetic flux |
e) magnetic field |
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Faraday discovered a) the Right Hand Rule for conductors |
b) that a conductor will have a voltage induced if it cuts magnetic flux |
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If a conductor is held stationary and a magnetic field is moved across it, it forms what is known as a) motor action |
c) generator action |
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When a conductor is moved to cut magnetic flux lines at an angle of 90 degrees a) maximum resistance to current flow is attained |
d) voltage generated will be maximum |
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When magnetic flux lines travel and meet in opposing directions the result can be a) generator action |
d) motor action |
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A conductor supplied with current while in a magnetic field will a) tend to move at right angles to the flux lines |
a) tend to move at right angles to the flux lines |
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If two unlike poles are placed adjacent to each other there is a) a force of repulsion between the magnets |
d) a force of attraction between the magnets |
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When current flows in a conductor a) A.C. voltage is generated |
e) a circular magnetic field is set up around the conductor |
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The total number of lines of force per square metre a) known as the EMF |
c) called the magnetic flux |
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Magnetic field direction and intensity depend on the a) temperature of the EMF |
e) specific heat of the conductor |
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When like poles of a magnet are placed adjacent to each other they will a) be attracted to each other |
d) repel each other |
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A property of a magnet is that it will always point in the north and south direction, when a) submerged in oil |
e) freely suspended in the air |
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If two unlike poles are placed adjacent to each other there is a) a force of repulsion between the magnets |
d) a force of attraction between the magnets |
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When current flows in a conductor a) A.C. voltage is generated |
e) a circular magnetic field is set up around the conductor |
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The total number of lines of force per square metre in a magnetic field is a) known as the EMF |
c) called the magnetic flux |
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Magnetic field direction and intensity depend on the a) temperature of the EMF |
d) direction and intensity of current flow |
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When like poles of a magnet are placed adjacent to each other they will a) be attracted to each other |
d) repel each other |
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A property of a magnet is that it will always point in the north and south direction, when a) submerged in oil |
e) freely suspended in the air |
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Iron and steel may be magnetized by rubbing the metal with a) stainless steel |
d) a magnet |
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The property which determines whether or not a material will be easily magnetized or not is called a) reaction |
e) permeability |
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The property of resistance to conducting magnetic lines of force is known as a) resistance |
b) reluctance |
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The maximum voltage generated by a single loop DC generator occurs when the conductor is cutting the magnetic lines of force at an angle of a) zero degrees |
c) 90 degrees |
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When using Fleming's Left Hand Rule, the index finger represents a) generator action flux direction |
d) motor action flux direction |
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A current carrying conductor being moved by a a) magnetic flux |
e) motor action |
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The direction of the ______________ due to motor action may be determined using the Left Hand Rule. a) force |
a) force |
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The minimum voltage generated by a single loop DC generator occurs when the conductor is cutting the magnetic lines of forces at an angle of a) 45 degrees |
d) 180 degrees |
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The right hand rule is used to a) indicate the speed of a rotor |
b) determine the direction of induced current flow |
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Batteries a) do not pose any immediate electrical hazards |
d) produce a steady DC voltage |
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The most common measurement made with a meter is a) amperage |
d) voltage |
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When using an electrical meter to check that a circuit is safe to work on, it is important to verify the proper scale, a) it may appear that no voltage or current is present and therefore safe |
a) it may appear that no voltage or current is present and therefore safe |
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A clamp-on ammeter measures current flow by using a) differential voltage |
c) a basic transformer principle |
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Clamp-on ammeter readings may be inaccurate if a) jaws are dirty or misaligned |
a) jaws are dirty or misaligned |
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A kilowatt hour meter has a small motor which a) turns at a constant speed |
c) has a speed proportional to power consumption |
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Utility companies have a surcharge to their customers based on a) the maximum voltage used |
e) peak demand |
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A voltmeter is connected to a circuit a) in series |
d) in parallel |
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Ammeters are connected with the negative or black lead connected to the a) positive side of the circuit |
c) negative side of the circuit |
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When reading the dials of a power meter, read a) them in the sequence shown by the letters under each |
d) them from right to left |
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The black demand pointer of a power meter a) moves the red pointer |
e) must be manually reset |
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The electromagnetic field for a DC machine is termed the a) armature |
c) field poles |
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There are three main types of DC generators; series, shunt and compound wound. Each is a) separately excited |
d) self-excited |
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Alternators must run at constant speed in order to maintain a) current |
e) frequency |
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The output voltage of a shunt dc generator may be varied by adjusting the a) field rheostat |
a) field rheostat |
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The main components of a DC machine are the yoke or frame which supports the __________________ and the rotor which is called an armature. a) wiring |
b) field poles |
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In order to produce the strength of magnetic flux required in larger DC machines a) electromagnets are used |
a) electromagnets are used |
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The armature core of a DC machine is built up of laminations of a) copper bars |
e) silicon steel plates |
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A shunt type DC generator has __________ output voltage. a) very high |
b) nearly constant |
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The magnetic field in a DC machine may be supplied by permanent magnets in small units. Large DC machines use field poles that a) insulators |
e) electromagnets |
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The three main types of DC generators are the: 1. compound wound a) 1, 3, 5 |
a) 1, 3, 5 |
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The load current has no effect on the field excitation of a a) compound wound generator |
d) separately excited generator |
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Three factors which control the electromotive force developed by a DC generator are the: 1. size of the frame a) 1, 3, 6 |
b) 2, 3, 5 |
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The voltage produced in each phase of a three phase generator is displaced by __________ electrical degrees from the other a) 120 |
a) 120 |
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The field strength of an alternator can be adjusted by varying the amplitude of the DC power supplied to the a) rotating field |
a) rotating field |
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The field strength of an alternator may be changed by varying the amplitude of the DC power, supplied to the rotating field by: 1. the use of a field rheostat a) 1, 2, 3 |
b) 1, 4 |
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An advantage of having an alternator with a rotating field is, that the size of the rotating mass is a) constant |
c) reduced |
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The connection provided on DC motors to supply the armature with power a) are slip rings |
d) is a commutator |
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A common use for a DC generator is a) power supply for an elevator |
a) power supply for an elevator |
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In a series wound DC generator a) brushes do not change AC to DC |
c) load current passes through the field windings |
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A rheostat or "voltage regulator" of a DC shunt wound generator is used to a) regulate the strength of the electromagnetic field |
a) regulate the strength of the electromagnetic field |
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When synchronizing an alternator; voltage, phase and frequency must all be the same as well as a) phase sequence |
a) phase sequence |
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The field rheostat in a DC generator is used to adjust the _______________ of the motor. a) direction of rotation |
c) output voltage |
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The coils or windings on a DC machine armature, are placed in _____________ cut in the face of the armature. a) bars |
e) slots |
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The commutator of a DC machine is made of copper bars mounted in a) glass |
b) micanite |
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The field rheostat changes the _______________________ in a DC generator. a) output voltage |
a) output voltage |
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A compound wound DC generator has a combination of shunt and ___________________ characteristics, depending on the a) parallel |
d) series |
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The strength of the magnetic field produced in a shunt wound generator a) is weak |
b) is fairly constant |
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A compound wound DC generator may have three characteristics which are a: 1. decreasing output voltage versus load a) 1, 2, 4 |
c) 1, 3, 5 |
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The output voltage rises sharply from minimum load to full load conditions for DC wound generators, if constructed with one of the following systems: a) shunt |
d) series |
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The rotating field of an alternator is obtained by exciting the windings on the rotor with a) AC power |
d) DC power |
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The stator of an alternator is built of ________________ mounted in a frame. a) copper alloys |
b) silicon steel |
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A 6 pole alternator producing 60 Hz power must turn at a) 1800 rpm |
d) 1200 rpm |
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Alternators are constructed to use slip rings made of brass or a) copper |
e) steel |
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The number of cycles per unit of time measured in Hz, is known as a) time delay |
c) frequency |
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_____________________ are used on motors and generators to set up a magnetic field. a) Insulated wires |
e) Field poles |
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A rheostat is also known as a a) voltage regulator |
d) variable resistor |
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Shunt wound DC motors are common where speed must remain constant regardless of load such as on a) automobile starters |
b) machinist lathes |
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Three types of DC motors are shunt, series and a) reverse wound |
d) compound |
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Compound motors combine the characteristics of shunt and ______________ motors, as desired by the designer. a) AC |
d) series |
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The ________________________ of a DC machine is built up of laminated steel plates mounted on the shaft. The coils are connected to a commutator mounted on one end of the a) armature |
a) armature |
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The yoke that supports the main components of the DC machine is frequently made of a) copper or brass |
d) cast steel or iron |
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Synchronous motors have construction that is identical to a) reciprocating equipment |
e) alternators |
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An AC motor which will drop out of synchronism and simply trip when overloaded is the a) slip-ring induction motor |
d) synchronous motor |
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Permanent magnets are used for a) the largest DC motors and generators |
d) the smallest DC motors and generators |
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Brush gear for DC machines have brushes made from carbon because they: 1. are softer a) 2, 3, 5 |
c) 1, 2, 5 |
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A rheostat is used to __________ the field strength in a DC machine. a) stop |
d) vary |
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Synchronous motors are used to a) start alternators |
d) improve the power factor of a power system |
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To transfer the power to or from the rotor of alternators or some AC motors a) field poles are employed |
d) slip rings are employed |
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Apparent power is the power a) used for the actual work |
c) supplied by the utility |
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When magnetic flux produced by one coil induces an EMF in a second coil it is called a) self inductance |
c) mutual inductance |
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A transformer works on the principle of a) reverse polarity |
b) magnetic induction |
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Three major losses which occur in a transformer are iron losses, copper losses and a) cooling losses |
c) flux leakage |
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Copper losses in a transformer are reduced by a) using fan cooling |
c) using larger diameter wire |
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An active current transformer should never a) be inspected until properly grounded |
d) have its secondary circuit opened |
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A phenomena produced by electronic switchgear which can result in excessively high voltages in transformers are known as a) capacitive reactance |
e) harmonic distortion |
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A device used to change the voltage and current from one level to another, is known as a/an a) conductor |
d) transformer |
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An instrument transformer used to measure voltage is called a a) current transformer |
c) potential transformer |
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Transformers are rated in terms of: 1. Volt amperes a) 1, 2 |
e) 1, 3 |
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The capacity of a transformer can be increased by: 1. submerging the core and windings in a tank of oil a) 1, 3, 5 |
a) 1, 3, 5 |
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A transformer has a primary voltage of 500 volts and 20 turns on the primary winding. If the secondary winding has 5 turns the voltage of the secondary is a) 2000 volts |
c) 125 volts |
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The voltage induced in the secondary windings of the transformer, is ________________ turns ratio of the transformer. a) directly proportional to the |
e) inversely proportional to the |
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Current transformers step down the current rather than the a) resistance |
e) voltage |
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Transformer cooling oil has a) a very high specific heat |
a) a very high specific heat |
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Some of the hazards of transformer cooling oil can be compensated for by adding a) chelates |
c) chlorinated hydrocarbons |
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Transformers should be inspected at least a) quarterly |
d) annually |
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A typical extra low voltage device would be a a) toaster |
c) door bell |
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A prime factor in determining the voltage to be used in a circuit is a) transformer capacity |
c) degree of access to equipment |
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Low voltage systems may have an acceptable voltage variation of plus or minus a) 10% |
b) 5% |
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The ability of an electrical circuit to store a charge of a) hysteresis |
e) capacitance |
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When working with high voltage systems, the minimum distance of approach should be a) 1 metre |
c) 2 metres |
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The best type of diagram for showing supply and distribution systems is the a) riser diagram |
b) one-line diagram |
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An electrical distribution system is composed of service, feeders and a) secondary circuits |
c) branch circuits |
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The utility's responsibility will not go beyond the a) first branch line |
b) first overcurrent device |
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A power meter |
c) reads only a small percentage of the actual load |
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When AC action causes a counter current in a coil it is termed a) self inductance |
a) self inductance |
