Book 8

Question 1

Which unit is used to measure the magnitude of an electromotive force?

a.
Amps

b.
Electrons

c.
Ohms

d.
Volts

Answer 1

Volts

Question 2

When using the Left Hand Rule for Motors, the index finger represents:
Select one:

a.
Magnetic flux direction, for generators

b.
Conductor motion direction, for motors

c.
Flux direction, for motors

d.
Direction of current flow, for motors.

Answer 2

Flux direction, for motors

Question 3

Shunt wound DC motors are used where speed must remain constant regardless of load, such as on:
Select one:

a.
Automobile starters

b.
Elevators

c.
Lathes

d.
Traction engines
Feedback

Answer 3

Lathes

Question 4

Low voltages include all voltages between _____ V.
Select one:

a.
0 and 30

b.
30 and 220

c.
30 and 750

d.
100 and 750

Answer 4

30 and 750

Question 5

To transfer the power to or from the rotor of alternators, ____________ are used.
Select one:

a.
Field poles

b.
Commutators

c.
Slip rings

d.
Hard-wired connections

Answer 5

Slip rings

Question 6

The direction of the _____ on the conductor may be determined using the Left Hand Rule for Motors.
Select one:

a.
force

b.
polarity

c.
resistance

d.
voltage

Answer 6

force

Question 7

The instrument used to measure electrical power used in a period of time, is the:
Select one:

a.
Kilowatt hour meter

b.
Voltmeter

c.
Ohmmeter

d.
Milli-ammeter

Answer 7

Kilowatt hour meter

Question 8

If the power dissipated by a resistor is 1.2 kW when supplied with 110 V, the amperage will be _____ A.
Select one:

a.
91.666

b.
19.006

c.
10.91

d.
132

Answer 8

10.91

Question 9

The basic unit of electrical power is the watt, which is the product of:
Select one:

a.
Volts x resistance.

b.
Volts x ohms.

c.
Volts x amperes.

d.
Ohms x amperes.

Answer 9

Volts x amperes.

Question 10

What can be used so that one side of the loop is always connected to the same side of the external circuit?

a.
A commutator

b.
Brushes

c.
Slip rings

d.
An armature

Answer 10

Slip rings

Question 11

Transformers:
Select one:

a.
Step up or down AC voltage

b.
Transform AC voltage to DC voltage

c.
Rectify DC voltage to AC voltage

d.
Step up DC voltage

Answer 11

Step up or down AC voltage

Question 12

The black demand pointer of a kilowatt hour meter:
Select one:

a.
Moves the red pointer

b.
Reads the current demand

c.
Indicates the maximum voltage being drawn

d.
Must be manually reset

Answer 12

Must be manually reset

Question 13

Faraday discovered:
Select one:

a.
The Right Hand Rule for conductors

b.
That a conductor will have a voltage induced if it moves through a magnetic field

c.
The Left Hand Rule for motors

d.
The Left Hand Rule for generators

Answer 13

The correct answer is: That a conductor will have a voltage induced if it moves through a magnetic field

Question 14

Three resistances of 20, 50 and 80 Ω make up a series circuit. The supply voltage is 400 V. The current flowing would be:
Select one:

a.
2.67 A

b.
8 A

c.
5 A

d.
0.375 A

Answer 14

The correct answer is: 2.67 A

Question 15

Which of the following is NOT safe practice when operating a safety switch?

a.
Stand on the hinged side of the switch door

b.
Face the switch

c.
Walk away from the switch as soon as the switch makes contact

d.
Operate the switch with the non-dominant hand

Answer 15

The correct answer is: Face the switch

Question 16

Extra low voltages include all voltages below _____ V.
Select one:

a.
30

b.
50

c.
110

d.
220
Feedback

Answer 16

The correct answer is: 30

Question 17

A material that transfers electric charge is called:
Select one:

a.
An insulator

b.
A conductor

c.
A circuit

d.
A wire
Feedback

Answer 17

The correct answer is: A conductor

Question 18

Tie breakers are used to:
Select one:

a.
Allow the interconnection of two power sources without placing them in parallel

b.
Break the circuit in case of overload

c.
Protect the transformer from the power source

d.
Protect the plant service bus from the power source

Answer 18

The correct answer is: Allow the interconnection of two power sources without placing them in parallel

Question 19

The total circuit resistance is less than a value of any individual resistor:
Select one:

a.
When voltage is decreased

b.
When the resistors are wired in parallel

c.
If the amperage is increased

d.
When the resistors are wired in series

Answer 19

The correct answer is: When the resistors are wired in parallel

Question 20

The total number of lines of ________ in a magnetic field determine(s) the value or magnitude of the flux.
a.
Force

b.
Current

c.
Flux

d.
Volts

Answer 20

Force

Question 21

___________ are used on motors and generators to produce the strong magnetic field required by these machines.
Select one:

a.
Insulated wires

b.
Transformers

c.
Rheostats

d.
Pole pieces

Answer 21

Pole pieces

Question 22

Three resistors of 20, 60 and 120 Ω are connected in parallel with a current flow of 60 A. The applied voltage will be _____ V.
Select one:

a.
7200

b.
800

c.
13.33

d.
0.33

Answer 22

800

Question 23

The right hand rule for generators is used to:
Select one:

a.
Indicate the speed of a rotor

b.
Determine direction of induced current flow

c.
Determine the frequency of an alternator

d.
Determine magnetic flux rotation

Answer 23

Determine direction of induced current flow

Question 24

The strength of the magnetic field produced in a shunt wound generator:
Select one:

a.
Is weak

b.
Is fairly constant

c.
Is regulated by an external AC supply

d.
Increases with generator load

Answer 24

Is fairly constant

Question 25

A triple pole single throw switch is one that: Select one: a. Opens and closes three wires of an electrical circuit b. Has three magnetic poles c. Is used for three phase circuits only d. Requires three toggles

Answer 25

Opens and closes three wires of an electrical circuit

Question 26

Which governing body assigns the frame numbers that designate specific external dimensions to motors? a. NFPA 70 National Electrical Code b. International Electrical Commission (IEC) c. CSA C22.1 Canadian Electrical Code (CEC) d. National Electric Manufacturers Association (NEMA)

Answer 26

National Electric Manufacturers Association (NEMA)

Question 27

Electromotive force: Select one: a. Moves electrons through a conductor b. Is able to move ohms through a resistance c. Is increased by a resistor d. Is increased by a voltage drop

Answer 27

Moves electrons through a conductor

Question 28

The opposition that a device or material offers to the flow of electric current is known as: Select one: a. resistance b. conductance c. voltage drop d. insulation

Answer 28

resistance

Question 29

If the applied voltage in a circuit is 120 V and the current flow is 3 A the resistance of this circuit is: Select one: a. 40 W b. 0.025 Ω c. 360 Ω d. 40 Ω

Answer 29

40 Ω

Question 30

The main components of a DC machine are the non-moving assembly, called the _____, and the rotor, which is also called an armature. Select one: a. Wiring b. Stator c. Rheostat d. Generator

Answer 30

Stator

Question 31

Electrons are negatively charged particles: Select one: a. Orbiting about the nucleus of an atom b. Firmly attached to the neutrons of an atom c. That can easily flow through insulators d. That seek open circuits

Answer 31

Orbiting about the nucleus of an atom

Question 32

Which component is responsible for electrical distribution and from the distribution network? a. Branch circuits b. Transformers c. Feeders d. Motor control center

Answer 32

Feeders

Question 33

When reading the dials of a kilowatt hour meter, read: Select one: a. Them in the sequence shown by the letters under each b. Them from left to right c. The ones that rotate clockwise first d. Them from right to left

Answer 33

Them from right to left

Question 34

Alternators are constructed with slip rings made of brass or: Select one: a. Copper b. Carbon c. Mica d. Steel

Answer 34

Steel

Question 35

In a series wound DC generator: Select one: a. Brushes change DC to AC for the armature b. The shunt winding is connected taps in before the series winding c. Load current passes through the field windings d. The shunt winding is connected after the series winding

Answer 35

Load current passes through the field windings

Question 36

Apparent power is the Select one: a. kW of power consumed b. VA supplied to a reactive AC circuit c. Power due to resistance in a circuit d. Power recorded by a kWh meter.

Answer 36

VA supplied to a reactive AC circuit

Question 37

Which of the following is not a type of electrical diagram? a. Connection or wiring diagram b. Electrical flow diagram c. Riser diagram d. Schematic or elementary diagram

Answer 37

Electrical flow diagram

Question 38

The voltage induced in the secondary windings of the transformer, is _____ the turns ratio of the transformer. Select one: a. proportional to b. reversed to c. opposed by d. inversely proportional to

Answer 38

proportional to

Question 39

What happens as conductors move parallel to the magnetic line of force? a. Maximum EMF is generated b. The right-hand rule must be followed c. The left-hand rule must be followed d. No EMF is generated

Answer 39

No EMF is generated

Question 40

Which meter is used to test the quality of a conductor’s insulation? a. Voltmeter b. Megohmmeters c. Ammeter d. Ohmmeter

Answer 40

Megohmmeters

Question 41

_____ is a unit of electromotive force. Select one: a. The Ampere b. The Ohm c. The Watt d. The Volt

Answer 41

The Volt

Question 42

Which equipment converts AC power to DC power? a. Transformer b. Inverter c. Transfer switch d. Rectifier

Answer 42

Rectifier

Question 43

What is the electromotive force developed by an alternator proportional to? a. Conductor speed b. Cycles produced at the alternator terminals c. Number of poles d. Number of phases

Answer 43

Conductor speed

Question 44

Permanent magnets are used for: Select one: a. Shunt motors b. Series motors c. Small portable alternators d. Induction motors

Answer 44

Small portable alternators

Question 45

When current flows in a conductor: Select one: a. AC voltage is generated b. The conductor develops north and south poles c. A circular magnetic field is set up around the conductor d. All magnetic forces are dissipated

Answer 45

A circular magnetic field is set up around the conductor

Question 46

The stator of an alternator is built of _____ mounted in a frame. Select one: a. Copper alloys b. Laminated steel sheets c. Carbon ring d. Armature conductors e. Non-metallic materials

Answer 46

Laminated steel sheets

Question 47

A clamp-on ammeter measures current flow by using: Select one: a. Shunting current through a milli-ammeter b. Differential current flow between two conductors c. A basic transformer principle d. A portion of circuit resistance

Answer 47

A basic transformer principle

Question 48

Which maintenance activity requires transformer to be de-energized? a. Using thermal imaging cameras b. Taking transformer readings c. Removing any panel or cover d. Checking containments Feedback

Answer 48

Removing any panel or cover

Question 49

When AC action causes a back EMF in the same coil of wire, it is termed: Select one: a. Self inductance b. Capacitance c. Mutual inductance d. Electromagnetic induction

Answer 49

Self inductance

Question 50

The voltage drop across a 20 Ω resistor with 10 A flowing would be _____ V. Select one: a. 2 b. 0.5 c. 200 d. 20

Answer 50

200

Question 51

The basic unit of mechanical or electric power is the: Select one: a. Volt b. Watt c. Ampere d. Ohm

Answer 51

Watt

Question 52

The equivalent resistance of three resistances of 10, 25 and 50 Ω connected in parallel is _____ Ω. Select one: a. 0.16 b. 6.25 c. 18.75 d. 8.5

Answer 52

6.25

Question 53

The load current has no effect on the field excitation of a: Select one: a. Compound wound generator b. Series wound generator c. Shunt wound generator d. Separately excited generator

Answer 53

Separately excited generator

Question 54

An instrument transformer used to measure voltage is called a: Select one: a. Current transformer b. Step down transformer c. Potential transformer d. Auto-transformer

Answer 54

Potential transformer

Question 55

Atoms that have greater than 3 electrons in the outer shell are: Select one: a. Positively charged b. Good conductors c. Neutrally charged d. Poor conductors

Answer 55

Poor conductors

Question 56

What power is dissipated by a resistor with a supply voltage of 120 V and a current of 8 A? Select one: a. 15 Ω b. 15 W c. 960 W d. 96 kW

Answer 56

960 W

Question 57

If a material provides resistance to magnetic flux, it is demonstrating: Select one: a. Resistance b. Reluctance c. Impedance d. Repulsion

Answer 57

Reluctance

Question 58

A compound wound DC generator has a combination of shunt and _____ characteristics, depending on the predominance of each type of winding. Select one: a. Parallel b. Separately-excited c. Induction d. Series

Answer 58

Series

Question 59

Which of the following is a requirement for synchronizing alternators? Select one: a. Amperages must be equal b. Voltages must be out-of-phase c. Phase rotations must be leading by 120 degrees d. Frequencies must be equal

Answer 59

Frequencies must be equal

Question 60

What is the correct reading off of this energy dial? a. 1463 b. 3641 c. 4641 d. 1464

Answer 60

3641

Question 61

An operating current transformer should never: Select one: a. Be inspected until properly grounded b. Have its primary circuit opened c. Produce excessively high voltages d. Have its secondary circuit opened first

Answer 61

Have its secondary circuit opened first

Question 62

Harmonic frequencies generate additional current within the transformer. What effect do these frequencies have? a. They tend to overheat and damage the transformer b. They have no effect on the transformer c. They tend to increase efficiency of the transformer d. They add to the total current generated

Answer 62

They tend to overheat and damage the transformer

Question 63

The yoke that supports the main components of the DC machine is frequently made of: Select one: a. Copper or brass b. Composite materials c. Steel or iron d. Aluminum

Answer 63

Steel or iron

Question 64

An AC motor which will drop out of synchronism and simply trip when overloaded is the: Select one: a. Slip-ring induction motor b. Induction motor c. Wound rotor induction motor d. Synchronous motor

Answer 64

Synchronous motor

Question 65

Single-phase transformers: Select one: a. Use two common forms of construction known as the core type and the shell type. b. High voltage coil is nearest the iron core. c. Use two common forms of construction known as the internal type and the external type. d. Are very low in efficiency.

Answer 65

Use two common forms of construction known as the core type and the shell type.

Question 66

Ammeters are connected: Select one: a. In parallel with the circuit b. In series with the circuit c. In parallel with the circuit to measure the resistance d. So that voltage will bypass the meter

Answer 66

In series with the circuit

Question 67

Current transformers are: Select one: a. Current step-up transformers b. K-type transformers c. High power factor transformers d. Voltage step-up transformers

Answer 67

Voltage step-up transformers

Question 68

The field strength of an alternator can be adjusted by varying the amplitude of the DC power supply to the: Select one: a. Rotating field b. Stator windings c. Rotating stator d. Pole pieces

Answer 68

Rotating field

Question 69

Alternators must run at constant speed in order to maintain: Select one: a. Current b. Power output c. Constant voltage d. Frequency

Answer 69

Frequency

Question 70

The voltage produced in each phase of a three phase generator is displaced by _____ electrical degrees from the other phases: Select one: a. 120 b. 90 c. 60 d. 30

Answer 70

120

Question 71

Watt meters measure: Select one: a. Apparent power b. Power factor c. Resistance to current flow d. Active power

Answer 71

Active power

Question 72

A voltmeter must ______________ electrical circuit. Select one: a. Offer low resistance to the b. Offer no resistance to the c. Offer slight resistance to the d. Offer high resistance to the

Answer 72

Offer high resistance to the

Question 73

A transformer works on the principle of: Select one: a. Hysteresis b. Mutual induction c. Eddy currents d. Kirchhoff's law

Answer 73

Mutual induction

Question 74

The minimum voltage generated by a single loop DC generator occurs when the conductor is traveling, relative to the magnetic lines of force: Select one: a. at an angle of 45° b. at an angle of 90° c. at an angle of 120° d. parallel to the lines of force

Answer 74

parallel to the lines of force

Question 75

The best type of diagram for showing supply and distribution system is the _____ diagram. Select one: a. Riser b. Single-line c. Connection d. Terminal and connection

Answer 75

Single-line

Question 76

In an atom the electrons: Select one: a. Orbit around each other b. Are repelled by the neutrons c. Are attracted to the protons d. Are large in size when compared to the protons

Answer 76

Are attracted to the protons

Question 77

The voltage required to force a current of 15 A through a resistance of 5 Ω will be _____ V. Select one: a. 3 b. 7.5 c. 33 d. 75

Answer 77

75

Question 78

Neglecting the efficiency of a 15 kW motor connected to a 400 V supply, the amperage will be _____ A. Select one: a. 26.667 b. 37.5 c. 0.0375 d. 3.75

Answer 78

37.5

Question 79

Brush gear for DC machines have brushes made from carbon because Select one: a. carbon is a good insulator b. carbon reduces the friction at the commutator c. carbon brushes are easy to manufacture d. they are inexpensive

Answer 79

carbon reduces the friction at the commutator

Question 80

Clamp-on ammeter readings may be inaccurate if: Select one: a. Jaws are dirty or misaligned b. Circuit voltage is too high c. Circuit resistance is too low d. Conductor insulation is too thick

Answer 80

Jaws are dirty or misaligned

Question 81

A common use for a DC generator is: Select one: a. Power supply for an elevator b. An automobile alternator c. Emergency power d. Power factor correction

Answer 81

Power supply for an elevator

Question 82

A basic law of electricity is, unlike charge attract each other and like charges: Select one: a. Repel each other b. Hold each other c. Attract each other d. Neutralize each other

Answer 82

Repel each other

Question 83

Find the line voltage when three resistors of 20 Ω, 30 Ω, and 40 Ω are connected in parallel. The current passing through the 20 Ω resistance is 1.5 A. Also determine the line current. a. 100 V, 9.23 A b. 60 V, 6.25 A c. 100 V, 18.46 A d. 30 V, 3.25 A

Answer 83

30 V, 3.25 A

Question 84

Transformers are often cooled by: Select one: a. immersing the core in a refrigerant bath b. forced cooling with fans c. immersing the core in cooling water d. using windings with less insulation

Answer 84

forced cooling with fans

Question 85

_____ current flow is from positive to negative. Select one: a. Alternating b. Direct c. Conventional d. Electron

Answer 85

Conventional

Question 86

The flow of electrons in a uniform direction is called: Select one: a. Voltage drop b. Electric current flow c. Potential difference d. Electromotive flow

Answer 86

Electric current flow

Question 87

An electrical distribution system is composed of service, feeders and: Select one: a. Secondary circuits b. Primary circuits c. Branch circuits d. Trunk circuits Feedback

Answer 87

Branch circuits

Question 88

A typical extra low voltage device would be a: Select one: a. Toaster b. Fluorescent light c. Door bell d. Step-down transformer

Answer 88

Door bell

Question 89

Copper losses in a transformer are reduced by: Select one: a. Using iron core laminations instead of copper b. Using larger diameter wire c. Reducing the primary voltage d. Increasing the secondary voltage

Answer 89

Using larger diameter wire

Question 90

The purpose of having an upward movement of a switch handle to close the switch is: Select one: a. To have the handle out of the way b. To meet the requirements of the electrical codes c. It indicates the condition of the circuit d. To prevent the switch from closing due to gravity

Answer 90

To prevent the switch from closing due to gravity

Question 91

A closed electrical circuit will: Select one: a. Close-off the flow of current b. Be series only c. Be parallel only d. Allow current to flow

Answer 91

Allow current to flow

Question 92

Low voltage systems may have an actual voltage variation of plus or minus: Select one: a. 10% b. 4% c. 1.5% d. 7.5%

Answer 92

4%

Question 93

If a conductor is held stationary and a magnetic field is moved across it, it behaves according to Select one: a. Motor action b. Electromagnetism c. Generator action d. Transformer action

Answer 93

Generator action

Question 94

Because of environmental concerns, it is no longer permissible to add ____________ to transformer oil. Select one: a. Anti-foaming substances b. Polyhlorinated biphenyls c. Freon d. Organic compounds

Answer 94

Polyhlorinated biphenyls

Question 95

The voltmeter is placed: Select one: a. In series with the ammeter b. In parallel with the circuit c. In series with the circuit d. Between the battery and the first resistance

Answer 95

In parallel with the circuit

Question 96

Three-phase transformers have: Select one: a. Three windings b. Two windings on the primary side and one on the secondary c. Six windings d. Nine windings

Answer 96

Six windings

Question 97

For three-phase power, each conductor is _____ electrical degrees out of phase with the others. Select one: a. 30 b. 90 c. 120 d. 180

Answer 97

120

Question 98

An electrical device that is designed to start and stop current flow is the: Select one: a. Power supply b. Fuse c. Circuit breaker d. Switch

Answer 98

Switch

Question 99

Current flow is: Select one: a. Increases as the applied voltage increases b. Proportional to the resistance c. Unaffected by resistance d. Increases when applied voltage decreases

Answer 99

Increases as the applied voltage increases

Question 100

If the line voltage ES is 120 V, what is the voltage drop across each resistor in a circuit that has a 15 Ω and a 25 Ω resistance connected in series? a. 2 A b. 1 A c. 4 A d. 3 A

Answer 100

3 A