Question 1

The torque reaches maximum when the rotor and stator currents are  ________with each other.

Accepted Answer

A)  in phase 
B)  60 degrees out of phase 
C)  120 degrees out of phase 
D)  150 degrees out of phase 
A)  in phase 
B)  60 degrees out of phase 
C)  120 degrees out of phase 
D)  150 degrees out of phase A

Question 2

A six-pole motor has a coil span of  ________.

Accepted Answer

A)  60 
B)  90 
C)  120 
D)  180 
A)  60 
B)  90 
C)  120 
D)  180 A

Question 3

How do primary resistance starters work?

Accepted Answer

The milling machines are equipped with primary resistance starters. For this type of starter or controller, the heavy starting current results in a voltage drop while it passes through the primary resistors; thus, there is a lower voltage value at the motor terminals. The motor accelerates gently with less torque than is the case when line starters are used. When the motor has almost reached its normal speed, a time-delay relay (set for about 5 seconds) closes a second contactor to short out the primary resistors. At this point, the motor receives the full line voltage and accelerates to its normal speed.

Question 4

Most dual-voltage single-phase motors will be of the ________ type, which contains both run and starting windings.

Accepted Answer

A)  monophase 
B)  split-phase 
C)  biphase 
D)  schematic 
A)  monophase 
B)  split-phase 
C)  biphase 
D)  schematic

Question 5

The speed of the wound-rotor induction motor can be controlled by the amount of  ________connected in the rotor circuit.

Accepted Answer

A)  capacitance 
B)  voltage 
C)  resistance 
D)  inductance 
A)  capacitance 
B)  voltage 
C)  resistance 
D)  inductance

Question 6

The force acting at the rim of the rotor multiplied by the radius from the center of the rotor is called the  ________.

Accepted Answer

A)  horsepower 
B)  torque 
C)  rotor speed 
D)  angular momentum 
A)  horsepower 
B)  torque 
C)  rotor speed 
D)  angular momentum

Question 7

Most dual­voltage motors bring out ________ "T" leads at the terminal box.

Accepted Answer

A)  three 
B)  six 
C)  nine 
D)  ten 
A)  three 
B)  six 
C)  nine 
D)  ten

Question 8

Direct-current compound motors contain a rotating armature and a(n)  ________field.

Accepted Answer

A)  stationary 
B)  interpole 
C)  commutator 
D)  brush 
A)  stationary 
B)  interpole 
C)  commutator 
D)  brush

Question 9

SCRs and GTOs are ________ and have the ability to handle a greater amount of current than transistors.

Accepted Answer

A)  thyristors 
B)  integrated circuits 
C)  resistors 
D)  capacitors 
A)  thyristors 
B)  integrated circuits 
C)  resistors 
D)  capacitors

Question 10

What factors play a role in the performance of dc motors?

Accepted Answer

The performance of a dc motor depends up

Question 11

The speed of the rotating magnetic field of a polyphase ac motor is called ________ speed.

Accepted Answer

A)  variable 
B)  critical 
C)  synchronous 
D)  proportional 
A)  variable 
B)  critical 
C)  synchronous 
D)  proportional

Question 12

The ________ operates like an electric check valve; it permits the current to flow through it in only one direction.

Accepted Answer

A)  inductor 
B)  diode 
C)  resistor 
D)  capacitor 
A)  inductor 
B)  diode 
C)  resistor 
D)  capacitor

Question 13

An induction motor is much like a(n) ________ , except that the secondary winding and core are mounted on a shaft set in bearings.

Accepted Answer

A)  limit switch 
B)  ohmmeter 
C)  transformer 
D)  voltmeter 
A)  limit switch 
B)  ohmmeter 
C)  transformer 
D)  voltmeter

Question 14

Three-phase motors can be constructed to operate in either wye or  ________.

Accepted Answer

A)  delta 
B)  star 
C)  Kennelly 
D)  cycle 
A)  delta 
B)  star 
C)  Kennelly 
D)  cycle

Question 15

Describe how rotation results in the squirrel-type induction motor.

Accepted Answer

The squirrel-cage type of induction moto

Question 16

What is the role of interpoles in dc motors?

Accepted Answer

Commutating poles or interpoles are very

Question 17

Although the  ________compound motor gives a more constant speed at all loads, the motor is somewhat unstable.

Accepted Answer

A)  armature 
B)  shunt 
C)  cumulative 
D)  differential 
A)  armature 
B)  shunt 
C)  cumulative 
D)  differential

Question 18

A(n) ________ uses two SCRs and two diodes.

Accepted Answer

A)  integrated circuit 
B)  transistor 
C)  bridge rectifier 
D)  inductor 
A)  integrated circuit 
B)  transistor 
C)  bridge rectifier 
D)  inductor

Question 19

What is the significance of the IGBT?

Accepted Answer

Many transistor-controlled variable driv

Question 20

In a machine that has a 3-phase motor rated at 460 volts, the current required by each machine is based on the ________of the motor.

Accepted Answer

A)  efficiency 
B)  volts 
C)  power factor 
D)  horsepower rating 
A)  efficiency 
B)  volts 
C)  power factor 
D)  horsepower rating

Exam 9: Motors and Controllers

The torque reaches maximum when the rotor and stator currents are ________with each other.

A six-pole motor has a coil span of ________.

How do primary resistance starters work?

Most dual-voltage single-phase motors will be of the ________ type, which contains both run and starting windings.

The speed of the wound-rotor induction motor can be controlled by the amount of ________connected in the rotor circuit.

The force acting at the rim of the rotor multiplied by the radius from the center of the rotor is called the ________.

Most dual­voltage motors bring out ________ "T" leads at the terminal box.

Direct-current compound motors contain a rotating armature and a(n) ________field.

SCRs and GTOs are ________ and have the ability to handle a greater amount of current than transistors.

What factors play a role in the performance of dc motors?

The speed of the rotating magnetic field of a polyphase ac motor is called ________ speed.

The ________ operates like an electric check valve; it permits the current to flow through it in only one direction.

An induction motor is much like a(n) ________ , except that the secondary winding and core are mounted on a shaft set in bearings.

Three-phase motors can be constructed to operate in either wye or ________.

Describe how rotation results in the squirrel-type induction motor.

What is the role of interpoles in dc motors?

Although the ________compound motor gives a more constant speed at all loads, the motor is somewhat unstable.

A(n) ________ uses two SCRs and two diodes.

What is the significance of the IGBT?

In a machine that has a 3-phase motor rated at 460 volts, the current required by each machine is based on the ________of the motor.

Plans and Sitework

The Unit Substation

Feeder Bus System

Panelboards

Trolley Busways

Using Wire Tables and Determining Conductor Sizes

Signaling Systems

Basic Motor Controls

Motor Installation

Power Factor

Ventilating, Air Conditioning, and Other Facilities

System Protection

Lightning Protection

Luminaires

Site Lighting

Programmable Logic Controllers

Developing a Program for a Plc

Fiber Optics

Hazardous Locations

Harmonics

Filters

Most dualvoltage motors bring out ________ "T" leads at the terminal box.