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107 Cards in this Set
- Front
- Back
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Indicates the period of time in which the motor will run fully loaded at rated speed without overheating and exceeding a predetermined temp rise.
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Duty (Time rating)
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A percentage the motor can be overloaded for a period of time.
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Service Factor
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The service factor is used to find the amount of ----- the motor can handle safely.
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Overload protection
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Safe overload for a motor is:
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FLA (SF)
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Designed to decrease breakaway torque of a motor.
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Bearings
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What are the three types of bearings?
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- Sleeves
- Ball - Roller |
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What are the low voltage connections for motors?
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L1-1-7
L2-2-8 L3-3-9 4-5-6 |
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What are the high voltage connections for motors?
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L1-1 4-7
L2-2 5-8 L3-3 6-9 |
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----- is the resistance to current leakage through and over the surface of insulation.
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Insulation resistance
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Insulation resistance values for each complete power circuit shall be .....
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at least one megohm
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Insulation resistance values for each complete lighting circuit shall be....
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at least .5 megohms
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Factors that affect insulation resistance:
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construction, moisture, temperature, cleanliness, condition of insulation
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Use of a ----- is used to get equivalent readings from different temperatures.
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Nomograph
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Information should be entered in the Machinery History concerning such matters as:
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repairs, alterations, inspections, safety device deficiencies, casualties, failures, parts renewal including important part numbers, and clearance measurements.
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The Index block of a resistance test record card usually indicates the ----- for the machine
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MPC number
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Insulation resistance values for each complete lighting circuit shall be....
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at least .5 megohms
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Factors that affect insulation resistance:
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construction, moisture, temperature, cleanliness, condition of insulation
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Use of a ----- is used to get equivalent readings from different temperatures.
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Nomograph
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Information should be entered in the Machinery History concerning such matters as:
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repairs, alterations, inspections, safety device deficiencies, casualties, failures, parts renewal including important part numbers, and clearance measurements.
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The Index block of a resistance test record card usually indicates the ----- for the machine
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MPC number
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(For the resistance test record) Given the test results, plotted at their appropriate interval and value, the trend can indicate the need for -----
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cleaning and overhaul
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Winches installed aboard ship are used to -----
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heave in on mooring lines, hoist boats, lift booms, and handle cargo.
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Winches are classified by -----
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-Drive Unit
-Type of design -drum -gypsy |
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Winches designed in accordance with military specifications for shipboard use are normally designed to have the following capabilities---
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-To haul in/pay out rated load at rated speed
-To haul in/pay out 150% of rated load at NO specific speed. -To withstand static load of 200% rated load without damage/distortion to winch. |
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This type of winch will have one to four horizontally mounted drums on which wire rope is wound. It is primarily used for raising, lowering, pulling loads and may be equipped with one or two gypsy heads.
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drum winch
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This type of winch has one or two horizontally mounted gypsy heads around which several turns of line must be taken to prevent slippage when a load is snaked (wrapped) or hoisted.
(Same as Drum, except (no drum), only the Gypsy head) |
Gypsy Winch
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The most common winch drives are.....
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-Electro-hydraulic - consists of a constant speed electric motor, which drives a variable displacement hydraulic pump.
-Electric (AC or DC) - Consists of electric motor, which operates the drive shaft through reduction gears. |
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The ----- is similar to the gypsy winch except that the gypsy head is mounted vertically.
(Intended primarily for warping and mooring) |
Warping Capstan
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The ----- is very similar to the warping capstan except:
-Has a hand-operated brake to control the feed of the anchor chain. -Has to engage the drum to the shaft manually to raise the anchor and anchor chain. |
Anchor Windlass
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(For Deck machinery maintenance) Perform the following to the brake system:
-Brake Controller Box -Inside box, locate the "--" leads -Megger leads; ensure they are not grounded. |
B
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An electromechanical device that requires the physical contact of an object with the switch's actuator to make the contacts change state.
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Limit switch
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A device that coordinates two or more circuits and prevents one operation from interfering with another.
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Interlock switch
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Magnetically actuated devices that sense component positions. consists of a switch circuit and a housing with a bayonet connector on one end and a magnetic-sensitive area on the other end.
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Proximity switch
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Force-balance devices, measuring weight as a change in pressure of the internal filling fluid.
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Hydraulic load cell
As force increases, the pressure of the hydraulic fluid rises. This pressure can be locally indicated or transmitted for remote indication or control. |
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An electromagnetic device whose function is to bring a load to rest mechanically and hold it at rest.
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Electric Brake
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The controller will disconnect the motor from the power supply and keep the circuit de-energized until the power is restored.
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Low Voltage Release
(LVR) |
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The controller will disconnect the motor from the power supply and must be restarted by the operator when the power is restored.
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Low Voltage Protection
(LVP) |
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List three types of watertight enclosures.
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-Drip proof
-Spray tight -Submersible |
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These enclosures are fitted with gaskets and filters, which prevent dust and dirt from entering the enclosure?
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Dust tight enclosures
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These enclosures are used in location where combustable atmospheres are present or may be encountered?
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Hazardous Location Enclosures
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Electromechanical devices that operate relays, contactors, and starters, the magnetic field attracts a plunger or armature near the core and will be pulled toward the coil assembly.
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Solenoid
They also provide a means of remote or automatic operation. Solenoids act like an electrically operated switch. |
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Solenoid-operated switches used to open or close motor control and pilot circuits. They normally control contactor coils.
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control relays
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Solenoid-operated switches similar in construction to control relays, which provide a safe and convenient means of connecting and disconnecting motor circuits to the voltage source.
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contactors
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Contacts designed for high current carrying conductors.
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main contacts
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Contacts designed for control power?
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auxiliary contacts
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In a control diagram symbols are usually shown in the ----- state.
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de-energized
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----- are designed to interrupt the motor circuit to prevent damage to the windings and insulation.
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Overloads
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Three types of overload relays are:
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Thermal, Magnetic, and electronic
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A heat sensitive element with an overload heater connected in series with the motor load circuit.
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Thermal Overload
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Controllers having ----- overloads have a coil connected in series with the motor circuit to operate in a manner similar to a solenoid.
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Magnetic overload
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Uses solid-state equipment to measure how much amperage is being drawn on the motor to open the normally closed contacts.
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Electronic Overload
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Controllers having overload relays may have an ----- feature for use in an overload condition.
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Emergency Run
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A switch with contacts that return from operated condition to normal condition when the actuating force is removed.
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Momentary switch
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A switch that sustains the contacts after the plunger has been released, but has provisions for resetting.
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Maintained contact switch
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To close or establish an electrical circuit Before opening an electrical circuit. This prevents the switched path from ever seeing an open circuit.
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Make Before brake
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To close or establish an electrical circuit after opening an electrical circuit. This prevents the momentary connection of the old and new signal paths.
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Make after break
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Provides automatic control of temperature regulation equipment. It regulates the temperature of liquids or gases.
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Temperature switch
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Uses the expansion properties of a contained gas, operate the switch contact sets as follows:
-When the contained gas is heated, then the pressure in the bellows increases and it expands to operate the contacts. -When contained gas is cooled, then the pressure in the bellows decreases and it contracts to change the switch contacts position. |
Bellows-type temperature switch
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This switch is constructed of a bellows, which responds to variations in pressure by expanding or contracting.
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Pressure switch
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This switch has a float assembly, which rises and falls in response to the liquid level.
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Float switch
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This switch has a paddle or vane attached to contacts by a lever or linkage, to regulate or maintain the flow of liquids or gas through piping or ducts.
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Flow switch
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This switch allows the motion of machinery to pass a signal only when a predetermined limit has been reached.
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Limit switch
May use arms, levers, rollers, cams, or wedges that move. |
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Keeps the contacts closed or open (depending on which type) for an adjustable amount of time after they are energized or de-energized
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Timed contact switch
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These switches are magnetically actuated devices that sense component positions.
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Proximity switch
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Prevents two opposite contactors from being energized at the same time.
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Interlock switch
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For a ----- transformer you want the voltage to be stepped down.
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Control transformer
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A ---- is an over current protective device with a fusible member that is heated directly and is destroyed by the current that passes through.
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Fuse
(It is vital that you never replace the fuse with a fuse of a higher current rating. |
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Athena's SCR power controllers are designed to regulate AC power to electrical .....
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...heating processes, such as ovens, furnaces, heat sealers, etc
(Note: they are not designed to drive transformers, coils or other inductive-type loads.) |
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An SCR controller accepts an input signal, such as ----- from some signal conditioning device, e.g., an Athena temperature controller
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4-20 mAdc
(the combination of an Athena temperature controller and SCR power controller provide accurate, automatic temperature control.) |
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A ----- switched (zero-switched or burst fired) SCR power controller works by triggering at the moment when the value of a AC sine wave is at the baseline or "zero" voltage point.
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Zero-Crossing
(Proportioning action is obtained by varying the number of cycles on to the number of cycles off) Output is integrated by the heaters, which produce a smoothly proportioning heat output varying directly with the input signal. |
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A ----- type SCR power controller works by delaying the trigger pulse to some point in the half cycle of the AC wave.
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Phase-Angle
Increasing the control signal will cause the trigger pulse to occur earlier in the half cycle, thus delivering a greater portion of the wave to the load. |
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Name two types of Athena's SCR power controllers.
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Series 91Z - the "Z" suffix designates the controller as operating in the zero cross, zero voltage switched, or zero burst firing mode.
Series 91P - The "p" suffix designates the controller as operating in the phase-angle firing mode. |
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----- are found on synchronous motors, they are metal rings mounted on a rotor shaft providing a connection to an external circuit via brushes.
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Slip Rings/Collector Rings
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What are the three common types of AC motors used in the Coast Guard?
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Series
Synchronous Induction |
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What motor is also called a universal motor, because it can be hooked up to AC or DC?
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Series
(The field poles are wired in series with the rotor.) |
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Single phase or three phase ------ motors are used to drive generators. Its speed stays constant regardless of the load.
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Synchronous motors
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----- motors are the least expensive to manufacture and are most commonly used whether single phase or poly-phase.
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Induction motors
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Plates that house the bearings and support the rotor in the center of the stator windings.
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End Bells
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Insulated heavy copper wire, generally located at the bottom of the stator slots.
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Main or Run Windings
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Small or thin insulated copper wire, usually located on top of the main winding.
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Start Winding
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The ----- disconnects the start windings and the capacitor at 75% rated speed of the motor, or after 3-5 seconds.
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Centrifugal switch
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Thermally operated device designed to protect the motor from overloading.
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Overload protection device
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Overloads usually consist of a ----- and a ----- that is connected in series with the line, sensing the line current.
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Bimetallic element
Heater |
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Attached on top or on the sides of the motor, the ----- will cause current to lead voltage (ICE) increasing torque during start up.
A ----- is a temporary storage unit that has the capacity to store electrical energy and discharge the energy when required. |
Capacitor
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In an electrolytic Capacitor, the electrolyte consists of a solution of ------, ------, ------.
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glycol, borate, and water
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The recommended operating temperature for an electrolytic capacitor is -----.
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150 degrees Celsius
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Mainly used in permanent-split phase and dual capacitor motors, ----- caps are designed to be connected continually in the circuit.
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Oil filled capacitors
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The ----- rating is the maximum HP the motor can produce without burnout.
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Horsepower rating
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1 HP = ---- watts
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746
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1 HP is the equivalent of moving ----- pounds one foot in one second.
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550
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What are the two different types of RPM ratings for a motor?
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Rated speed
Synchronous speed |
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The ----- speed of a motor is located on the nameplate and is the speed of the shaft.
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rated speed
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Synchronous speed is the speed of the ----- on a motor.
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rotating magnetic field
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Synchronous speed =
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120(freq)/# of poles
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# of poles =
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120(freq)/rated speed
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----- is the difference between rated speed and synchronous speed expressed as a percentage.
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Slip
The amount that the speed of the shaft is lagging behind the rotating magnetic field. |
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On a motor the voltage must be maintained plus or minus -----% for reliable operation.
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10
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When the motor is operating at the rated voltage and rated load (HP), the motor amperage should be the same as the ....
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FLA
full load amps |
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A motor drawing ---- amperage is not producing the rated HP.
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Lower
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A motor drawing ----- current is being overloaded.
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More
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Frame numbers are designated according to -----.
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Horsepower
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------ and ----- set the standards for frame sizes.
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NEC and NEMA
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A motor must always maintain plus or minus ----% of rated frequency to prevent damage.
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5 %
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Indicates a motors starting current surge
"Letter Code" found in the electric motor repair book by Rosenberg. |
KVA Code
kilo volt amp |
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The allowable temp that the motor can get before it destroys the insulation on the motor windings
All temps are expressed in degrees Celsius |
"insulation class"
found on nameplate data A-105 N-200 B-130 R-220 F-155 S-240 H-180 |
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Varnishing: Dipping and baking varnish onto the main windings adds:.....
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- Adds an extra value of insulation
- Secures the wire on the rotor - Provides a path for heat to escape |
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The max temp at which the motor can be operated.
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ambient temperature
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