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140 Cards in this Set
- Front
- Back
The ____ motor types are generally the most rigged |
Squirrel Cage |
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GROUNDING: To be effective, a grounding system must limit the voltage on the electrical system and protect it from all of the following except ____ |
Under voltage conditions |
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Any exposed live parts operating at ______ or or more between terminals must be guarded. |
50v |
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Motor circuits are covered in ______ . |
NEC Article 430 |
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There are _______ NEMA designated motor designs. |
6 |
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A _______ enclosure is totally enclosed. |
Explosion proof |
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The _______ represents the stationary magnet of a DC motor. |
Field poles |
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The _______ motor has the low start torque, low efficiency and high noise |
Shared Pole |
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The minimum diameter of galvanized pipe allowed for a grounding electrode is _______. |
¾" |
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A grounding clip is used to _______. |
Secure equipment grounding conductors to metallic outlet boxes |
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An acceptable group ding electrode is a _______. |
Metal frame of a building which is effectively grounded |
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Plate electrodes made of iron or steel must be at least _______ thick |
¼" |
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If non-metallic boxes are used with MN cable, which of the following is true? |
NO connection to the box is required MN : non-metallic sheathed Romex |
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If the frequency of an AC circuit is 15 cysts per ¼ second the Hertz rating of the circuit is _______. |
15cycles X ________ = ___ 60Hz .25 sec. 1 sec |
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The sign of 0° is _______. |
0 |
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A transformer has 200 turns in the primary, 150 turns in the secondary and 1206AC applies to the primary. The voltage across the secondary is _______. |
200 150 ___ = ____ 90volts 120 X 200x 150 x 120 ____ = __________ 200 200 X = 90v |
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The self induced voltage across an inductance L is produced by a change in current with respect to _______. |
Time |
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The total capacitance of a 20-microfrarad capacitor in parallel with a 10-microfarad capacitor is _______. |
CEQ = C1 + C2 = 20 + 10 In parallel 30microfarads |
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Motor: they + app The output capacity of a motor is measured in? |
Horsepower |
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AC The average voltage value in a circuit with a peak voltage of 170v is _______. |
108v |
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Spring back is a term used to describe the _______. |
Tendency of the conduit to relax to a bend angle slightly less than that indicated on the bender pointer when the bender is released |
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The FLA rating of a motor will be found on the _______. |
Name plate |
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The most common service factor appearing on a motor name plate is _______. |
1.15 |
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The best application for a shaded-pole motor is |
Small Fans Shaded Pole Motor - AC Single Phase Induction Motor - Small Squirrel Cage Motor in which the AUX winding is composed of a copper ring or bar surrounding a portion of each pole.AUX single turn winding is called a SHADING COIL. |
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If the time for a cycle is 0.1 seconds the frequency is |
10 1 --- = 10 .1 |
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Meters used in AC circuits indicate the _______ value. |
RMS value Root Means Square |
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A transformer with a primary of 400 turns and secondary of 300 turns has _______. |
Step-Down turns ratio of 4:3 |
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The secondary of a CT under load should NOT be opened because of _______. |
Induced High Voltage |
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If the area of the plates of a capacitor is increased the amount of capacitance _______. |
Increase |
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Conduit Bending The result of 2 kick bends in opposite directions in a conduit run will produce an _______. |
Offset |
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If a cold water pipe, driven ground rod and a grounding ring are available at a building site, _______ must be bonded to form the grounding electrode system. |
All of these |
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To prevent a one-shot bending shoe from digging in when bending rigid aluminum you should _______. |
Coat conduit with WD-40 or Petroleum Jelly |
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For a given number of poles, the _______ determine the speed of an AC motor |
Frequency |
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A transformer with 100 turns in its primary and 10 turns in its secondary is a _______ transformer. |
Step-Down |
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In an inductive circuit, the current at 180° is _______. |
0 |
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Unless otherwise noted, the calculations in AC circle use ______ values |
RMS Root Means Square |
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Both induction and synchronous motors operate on the principle of a rotating _______ field. |
Magnetic |
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The two dimensions an electrician must know when making a 90° stub bend are the |
Desired rise and take-up distance |
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A plate electrode must have AT LEAST _______ square feet of surface area exposed to the surrounding earth |
2sqft |
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Portable mechanical conduit benders can be used as one-shot benders on _______ |
Smaller sizes of conduit |
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When making offset bends the two kicks must be made perfectly parallel or the resulting offset will have a _______. |
Dog Leg |
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In AC circuits containing only resistance.... |
All DC rules and laws apply, including Ohm's law and Kirchhoff's law |
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The permanent ruining of metallic parts to form an electronically conductive path that ensures electrical continuity and the capacity to safely conduct any current that is likely to be imposed is called? |
Bonding |
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In a transformer... |
Electromagnetic Induction Occurs |
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In an AC circuit containing resistance only, _______ will flow if the resistance is 10 ohms and voltage is 120v |
12A E volts 1= --- amps= ------- R Ohms 120v -------- = 12A 10ohms |
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When making bends on short lengths of conduit, the shoe may be prevented from creeping by _______. |
Screwing a coupling on the conduit |
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When a ground rod is installed the top of the rod must be positioned _______ grade. |
Flush with or below |
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Hydraulic benders are capable of bending rigid pipe up to and including _______ in diameter. |
6" |
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The two types of shoes used in hydraulic bends are the _______ shoes. |
Are shot and segment |
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A grounding electrode conductor must be connected _______ of a main distribution panel |
To the natural terminal bus |
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The _______ method describes a ground test utilizing an earth ground resistance tester |
Three-point |
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Which of the following is NOT an advantage of an autotranferance? |
Being larger and stronger |
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The NEC requires that conductors connected to the high leg of a 4-wire delta system be color-coded with what color of insulation or tape? |
Orange |
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Heat Trace: Electric heat tracing of pipelines is done for all of the following reasons Except... |
To eliminate standard thermal insulation |
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Which type of heating cable cannot be cut and terminated in the field? |
Mineral Insulated |
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anesthetizing locations of hospitals are considered to be _______ locations? |
Class 1 Division 1 |
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In Hazardous locations were metal conduitis required, joints must be made up with at least _______ threads fully engaged. |
5 |
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_______ is approved for use in most Class 1 Division 1 locations. |
Rigid Met Conduit |
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A class 1 division 1 location is best described as an atmosphere that is _______ Hazardous |
Normally |
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The main purpose of seals of seal-offs in conduit runs is to______. |
prevent the passage of gases vapors, or flames from one portion of the system to another |
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The type of raceway approved for use in most hazardous locations is? |
Rigid Metallic Conduit |
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The type of cond body that provides a junction poi t for FOUR intersecting conduits is a _______ cond body |
X |
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The purpose of an insulated bushing at raceway termination points is to _______. |
Protect the conductors from being damaged |
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A type _______ cond body has a single cover opening to the right. |
LR It may look like an L (user) but I'm RIGHT. |
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The main purpose of an explosion proof flex coupling is to connect _______. |
Motors to a raceway system |
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The abbreviation for an entrance ell (elbow) is _______. |
SLB |
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A _______ square junction box must be used if there is one 6" cond. And two 4" conduit entering one side and exiting at 90° angle on the other side. (Conductor size is 4AWL or larger) |
44" 6"×6=36+4"=40+4"=44 |
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For a straight pull, the minimum length for a pull box with 2 (1" conduits) and 1 (4" conduit) on one wall and 2 (1" conduit) and 1 (4" conduit) entering opposite wall? |
32" 4"×8=32" Straight polls = no larger than 8× largest |
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A type _______ conduit boby had a threaded straight hub on each end and another threaded hub perpendicular to these two. |
T |
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Fact or Fiction: Capacitors are covered in NEC Art 460 |
FACT |
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If the heater in a fixed IEC bimetallic overload relay fails _______ |
The entire overload relay needs to be replaced. |
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Motor controls: A relay designated as a 3 PDT-SB relay _______. |
Has 3 NU and 3 NC (normally closed) contacts |
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Fact or Fiction Transformers are covered in NEC art 450 |
Fact |
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The minimum voltage needed to keep a relay coil energized is called the _______ voltage. |
Seal-in (to keep) |
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The NEC states that floors of transformer vaults on contact with the earth must be made of _______. |
4" concrete |
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Fact or Fiction Resisters and reactors are covered in NEC Art 470 |
Fact |
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Melting alloy heater assembly - consists of heater element and solder pot. The pot holds the ratchet. Motor overload wheel in on position. Excessive current passes through the heater element and melts the pot. Because the ratchet wheel is free to run in the molten pool. It trips a set of NC contacts in the starter, stopping the motor. |
*suppose to be a picture on the test |
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Overload Contact |
• |
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When voltage is stopped down in a transformer, what happens to the current in the same circuit? |
It is stepped up V⬇️ A⬆️ |
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Which of the following can be used to visually check for leakage flux? |
Iron Filling |
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The name plate on a motor indicates that the motor has an ELC of 13A and a service factor of 1.15. The additional current this motor can safely handle for intermittent power demand is? |
1.95A
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DISTRIBUTION SYSTEM TRANSFORMER: Which of the following best describes mutual induction? |
The condition in which two circuits share the energy of one circuit |
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When sizing outlet boxes, the conductor equivalent of a cable clamp is? |
1 |
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When sizing outlet boxes, the conductor equivalent of a switch is? |
2 |
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When calculating outlet box capacity, each duplex receptacle counts as _______ conductors? |
2 |
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The minimum depth required by the NEC for a round box is? |
½" |
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What type of condulet is not a pulling point for conduit that requires a 90° change in direction? |
Pulling C |
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Which of the rolling transformer types would you use to convert a lower-than-required voltage on a 120/208v system? |
Buck- and -Boost transformer |
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CONDUCTOR INSTALLATIONS: Where several conductors are pulled together, they should be arranged _______ on the fish tape? |
Staggered |
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BOXES & FITTINGS: Another name for a conduit body? |
Condulet |
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What is the recommended abrasive cloth used to clean cable during a splice? |
120 grit ALO |
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True or False: When installing most heating cables, avoid overlapping them. |
True |
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What is NOT a type of high voltage power cable? |
Category 5 |
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Hi pot testers for high voltage cable usually have a micrometer and a range dial to allow measurement up to ___MA, at which level the circuit breaker will trip or else the reactor will collapse. |
5MA |
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Acceptance tests are made at _______ of the original factory voltage. |
80% |
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Proof tests are made at _______ of the original factor voltage |
60% |
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What best describes a high voltage termination? |
An insulator |
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The outer shielding in a high voltage cable is best described as _______. |
Semiconductive layer under a metallic layer. |
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All of the following connectors may be used for splicing high voltage cables except _______. |
Split bolt connector |
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A quick test that can be made to determine if an installation is good is known as a _______ test. |
Go / no go |
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Of the terminator classes listed, _______ is the only one that provides a seal against external elements. |
Class 1 |
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The tough outer covering for a mechanical protection of a cable is called the _______. |
Jacket |
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HIGH VOLTAGE TERMINATION: If the original rubber insulation on a straight splice was ¼" thick, what is the minimum size it should be built up to? |
¾" |
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What is the classification and division of all floor level areas up to height of 18" in an airport hanger? |
Class 1 Division 2 |
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The higher the letter or # the least Hazardous For example... Class 1 Div 1 > class 2 Div 1 Group A > class 3 |
• |
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The most severe Hazardous class is.... |
Class 1 Division 1 |
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HAZARDOUS LOCATIONS: Definitions of Hazardous locations located NEC article 500 |
• |
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When the start and stop push buttons mounted in two or more control stations are connected into a motor control circuit, the start buttons must be connected in _______ and the stop in _______. |
Start -> Parallel Stop -> Series |
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The components used in domestic hot water temp maintenance systems are similar to those used in _______. |
Pipe heat tracing system |
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The requirements for the installation of electrical floor warming/ heating systems are defined in _______. |
NEC Art 424 |
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The scanning method in which a target is detected as it passes between a photoelectric sensor and reflector is called |
Retro reflective scann |
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A vented service pit in a commercial garage is a _______ location. |
Class 1 Division 2 |
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Intrinsically safe equipment is covered in NEC article 504 |
• |
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A permanent and effective seal is are method of preventing the entrance of dust into enclosures through a raceway system in class 2, Division 2 location another way is? |
Horizontal raceway not less than 10' in length |
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What best describes the devices that will help prevent moisture from collecting in raceway system? |
Integral Drains |
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The requirements for installing of electrical heat tracing cables on pipelines are defined in _______. |
NEC Article 427 |
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The term used to describe the repeated starting and stopping of a motor at frequent intervals of time for short periods of time is _______. |
Jogging |
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Heating cables installed in concrete for snow melting and anti-icing systems are typically spaced _______ on center. |
12" |
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Symbols |
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What type of wire is standard for low-voltage milliamp signal system? |
Single pair shielded |
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Several #12 age conductors are pulled together, how should they be arranged on a fish tape? |
Staggered |
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The voltage drop of conductors carrying alt. current in PVC conduit will have what relation to that of identical conductors in metal conduit? |
VD ⬇️ of AC current PVC > Metal More than |
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When transporting metal conduit it is best to... |
Keep the thread protection caps on to prevent damage to the threads |
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Electrical metallic tubing must be supported within what maximum distance from each junction or outlet box? |
3ft |
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What does a watt meter indicate? |
Watts = Power |
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The voltage of a DC circuit is to be measured. How should the volt meter be connected to ensure proper polarity? |
Negative terminal of meter to the reg or low potential pt in the circuit. The positive terminal of the meter to the positive or high potential pt in the circuit. |
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What is the resistance of a 1250 watt, 240 volt resistive heater. (Pic) |
5.2 amperes (answer on test) Or 46omh or resistance *it asks for resistance |
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What is the formula for calculating total resistance in a series circuit with 3 resistors? |
RT = R1 + R2 + R3 |
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The minimum acceptance DC megohm resistance of a 4,160v motor is approximately |
4.2 megohms |
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A voltage source of a circuit provides 240 volts and draws 48 amps. How much resistance is in the circuit? R = E = V = 240volts = 5ohms __ __ _________ 1 A 48 amps |
5 ohms Use R= E -- 1 |
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When three equal resistors are connected in parallel, the total resistance is.... |
Less than any one resistor |
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All of the following are correct formulas for "ohm's law" : (pic) Except .... |
E=P×I is not (Pic) |
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What is voltage? |
Electromotive Force |
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What is voltage? |
Electromotive Force |
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What is the source voltage in a circuit that consumes 1200 watts at a current of 5 amps? (Pic) |
240 volts (pic) |
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An analog voltmeter is being connected to a 24v DC circuit Polarity is reversed. What reading will occur? |
O or fewer volts |
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When a cable tray system must be protected from the sunlight, what should be used? |
Cable tray cover |
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A section of cable tray that makes two vertical 90° turns is known as... |
A vertical T (pic) |
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Which of the following is designed intended for high tension wire pulls? |
Nylon |
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A conduit piston (mouse/rat) is used for what application? |
Installing a pull line (jet line) |
