Electrical Theory Practice Test
What does it cost per year (at 8 cents per kWh) for the power loss of a 12 AWG circuit conductor (100ft long) that has a total resistance of 0.40 ohms and current flow of 16A?
$30
In a 3Ø circuit, how many electrical degrees separate each phase:
120
If a transformer has a voltage step-down from 117 volts to 6 volts then the ratio of the transformer is equal to what?
1: 19, 5
A three horsepower motor is equivalent to how many watts?
2238
Voltmeter
A high resistance is connected in series with the internal coil of a galvanometer to make?
The output of a 3-phase transformer is measured in what units?
Amperes
In order to calculate watt hours, which formulas must be used?
Amps/Volts (Amps Divided By Volts)
When reduced to the most nominal component, the smallest element of matter is...?
An atom
An eddy current can cause what?
An increase in core loss
What does Bonding do?
Controls the load on the system installation
What material is used on conduits inside and outside of a box?
Couplings
In a generator, voltage is produced by what...?
Cutting lines of force
Inductance and capacitance are not considerations in a DC current because?
DC supply carries power equally
In order to change the rotation of a DC series motor, what must be done?
F1 and F2 must be reversed.
Electric motors operate on the principle of induction and repulsion.
FALSE
In order to adjust the voltage of a constant speed DC generator, the field voltage must be changed.
FALSE
In order to connect an ammeter in series, the circuit must be opened at the voltage source and connected to the meter at the other end.
FALSE
The armature reaction in an alternator is magnetizing at lagging loads.
FALSE
What should be tested to check for voltage to ground?
From hot to neutral
Frequency is measured in...?
Hertz (Hz)
A negative charge will do which of the following: 1. I. Interact with negative charges 2. II. Interact with positive charges 3. III. Cause a short in a positive system
I & II
A capacitor performs what?
It creates changes in amperage
If a circuit breaker is installed vertically and the handle is flipped up, then the circuit breaker will be what?
Locked in place
A meter used to measure both AC and DC voltage and current is known as?
Multimeter
The most power lost in the form of heat would come from what?
Resistance
Of all of the materials used for insulation, which one has the highest electrical breakdown strength and the longest life?
Rubber
For electroplating power, which of the following generators should be used?
Split phase
Rearranging the control components in an electrical diagram in order to simplify tracing of a circuit is an example of a schematic diagram.
TRUE
The peak value of AC voltage determines the breakdown voltage of insulation.
TRUE
In a coil, the higher the level of self-inductance:
The longer the delay will be in establishing current through it
If a series circuit has unequal resistances throughout the circuit, then which of the following is true:
The lowest resistance has the highest voltage.
The efficiency of electrical equipment is determined by what?
The motor speed divided by the input power
If a transformer ratio is 20/1, what does it mean for the secondary?
The primary voltage is 20 times greater than that of the secondary.
If the power factor of a circuit is increased, then what occurs?
The reactive power is decreased
In a transformer, the side with more turns is what?
The secondary
Two transmission wires create a corona when...?
The wires are installed overlapping or too close together
Electrical appliances shall be installed in parallel in order to make the operation of each appliance in- dependent of the others.
True
Ground fault protection for personnel on a 120 volt single-phase circuit is based on?
Unbalanced current between the grounded and ungrounded conductor.
If a motor enclosure is designed to contain sparks or flashes that could ignite surrounding vapors or gases, then the enclosure is considered to be which of the following:
Ventilated
The electrical property of conductors that allows them to oppose the free flow of current traveling over them is measured in what?
Volts
Power factor is equal to...?
Watts multiplied by amps