Question 1

A centrifugal switch disconnects the start winding from the motor circuit when the motor reaches ____% of its rated speed.
A) 25
B) 50
C) 75
D) 90

Accepted Answer

A centrifugal switch typically disconnects the start winding from the motor circuit when the motor reaches about 75% of its rated speed. This allows the motor to continue running on the main winding alone.

Question 2

A ____ operates on the principle of a magnetic field instead of expanding metal.
A) current relay
B) hot-wire relay
C) solid state relay

Accepted Answer

A

Question 3

Because it is intended for continuous use, the capacitor of a capacitor-start capacitor-run motor is generally a(n) ____ type.
A) electrolytic
B) oil-filled
C) distribution
D) reactive

Accepted Answer

Oil-filled capacitors are suitable for continuous use as they are more durable and have higher capacitance stability compared to electrolytic capacitors. Distribution capacitors are used for power factor correction in certain applications, and reactive capacitors are used for reactive power compensation.

Question 4

The capacitor-start capacitor-run motor is designed so that the ____ while the motor is energized.
A) start winding is disconnected and the run winding remains connected
B) run winding is disconnected and the start winding remains connected
C) both the run winding and the start winding remain connected

Accepted Answer

In a capacitor-start capacitor-run motor, both the start winding and the run winding remain connected while the motor is energized to provide better starting torque and efficient running performance.

Question 5

Because the Holtz motor has a rotor cut with six slots, the motor speed produced is ____ RPM.
A) 3600
B) 1800
C) 1200
D) 900

Accepted Answer

The speed of a motor is determined by the formula: Speed (RPM) = (120 x Frequency) / Number of Poles. A Holtz motor with a rotor cut with six slots typically implies a 6-pole motor. Assuming a standard frequency of 60 Hz, the speed would be (120 x 60) / 6 = 1200 RPM.

Question 6

When determining the direction of rotation of a motor, you should be looking at the ____ of the motor.
A) left side
B) right side
C) front
D) rear

Accepted Answer

The answer of When determining the direction of rotation of...

Question 7

A motor with 8 stator poles will have a rated speed of approximately ____ RPM.
A) 3600
B) 1800
C) 1200
D) 900

Accepted Answer

The answer of A motor with 8 stator poles will...

Question 8

A motor that has 4 stator poles will have a rated speed of approximately ____ RPM.
A) 3600
B) 1800
C) 1200
D) 900

Accepted Answer

The rated speed of a motor is calculated by the formula:
RPM = (120 x Frequency) / Number of Poles
For a motor with 4 stator poles, the RPM can be calculated as:
RPM = (120 x 60) / 4 = 1800
Therefore, the correct answer is B, with a rated speed of approximately 1800 RPM.

Question 9

The capacitor-start induction-run motor produces a starting torque that is ____ that of the resistance-start induction-run motor.
A) higher than
B) lower than
C) about the same as

Accepted Answer

The capacitor-start induction-run motor produces a starting torque that is higher than that of the resistance-start induction-run motor. This is because the capacitor-start induction-run motor uses a capacitor to create a phase shift that provides a higher starting torque.

Question 10

Since both the start winding and the run winding of a capacitor-start capacitor-run motor remain energized at all times, the motor operates as a ____-phase motor.
A) one
B) two
C) three

Accepted Answer

A capacitor-start capacitor-run motor operates as a two-phase motor, where the two phases are shifted in time by the capacitor. The start winding and the run winding are both energized, which creates two magnetic fields shifted by a small angle of a few degrees. This allows the motor to rotate smoothly and generate high starting torque.

Question 11

To reverse the direction of a shaded-pole motor, you need to ____.
A) reverse the leads of the start or the run winding
B) reverse the leads of both the start and run windings
C) remove the stator winding and turn it around

Accepted Answer

Shaded-pole motors are a type of single-phase AC motor that do not have start or run windings that can be reversed. To change the direction of rotation, the physical orientation of the stator winding must be altered, effectively turning it around.

Question 12

When connecting a dual voltage motor for high voltage, the leads must be connected in ____.
A) parallel
B) series
C) series-parallel

Accepted Answer

Connecting the leads of a dual voltage motor in series will result in a higher voltage, while connecting them in parallel will result in a lower voltage. Series-parallel connections are also possible but not necessary for switching between high and low voltage.

Question 13

Because the start winding is wound with smaller wire and placed near the top of the stator, it will have ____ the run winding.
A) higher resistance than
B) lower resistance than
C) the same resistance as

Accepted Answer

The start winding is designed to have higher resistance than the run winding. This difference in resistance helps to create the phase shift needed to start the motor, as well as to prevent the start winding from overheating during normal operation.

Question 14

A thermistor is a device that exhibits a change of resistance with a change of ____.
A) voltage
B) amperage
C) power
D) temperature

Accepted Answer

A thermistor is a resistor whose resistance varies with temperature. As the temperature of the thermistor changes, so does its resistance. Therefore, the correct choice is temperature.

Question 15

The ____ functions as both a starting relay and an overload relay.
A) current relay
B) hot-wire relay
C) solid state starting relay

Accepted Answer

The hot-wire relay functions as both a starting relay and an overload relay by using a bimetallic strip that responds to both current and heat.

Question 16

Capacitors are rated in ____.
A) volts
B) farads
C) amperage
D) watts

Accepted Answer

Capacitors are rated in farads, which is a unit of electrical capacitance. The farad represents the amount of electrical charge that a capacitor can store per volt of applied charge.

Question 17

When the leads of the compensating winding of a universal motor are shorted together, the connection is known as ____ compensation.
A) conductive
B) inductive
C) reactive
D) capacitance

Accepted Answer

The answer of When the leads of the compensating winding...

Question 18

When a universal motor is operated on AC and the compensating winding is connected in series with the armature, it is known as ____ compensation.
A) conductive
B) reactive
C) inductive
D) capacitance

Accepted Answer

When a universal motor is operated on AC, and the compensating winding is connected in series with the armature, it is known as conductive compensation. This helps to reduce the reactance voltage drop and improve performance.

Question 19

The direction of rotation of a single-phase motor can be changed by reversing the connection of the ____.
A) start winding
B) run winding
C) either the start winding or the run winding
D) both the start winding and the run winding.

Accepted Answer

Either the start winding or the run winding can be reversed to change the direction of rotation in a single-phase motor.

Question 20

In motors, the speed of the magnetic rotating field is called the ____ speed.
A) rotating
B) power
C) split-phase
D) synchronous

Accepted Answer

The speed of the magnetic rotating field in motors is called the synchronous speed. This is because the speed is synchronized with the frequency of the power source. Therefore, the correct answer is D, synchronous.

Quiz 19: Single-Phase Motors

A centrifugal switch disconnects the start winding from the motor circuit when the motor reaches ____% of its rated speed.

A ____ operates on the principle of a magnetic field instead of expanding metal.

Because it is intended for continuous use, the capacitor of a capacitor-start capacitor-run motor is generally a(n) ____ type.

The capacitor-start capacitor-run motor is designed so that the ____ while the motor is energized.

Because the Holtz motor has a rotor cut with six slots, the motor speed produced is ____ RPM.

When determining the direction of rotation of a motor, you should be looking at the ____ of the motor.

A motor with 8 stator poles will have a rated speed of approximately ____ RPM.

A motor that has 4 stator poles will have a rated speed of approximately ____ RPM.

The capacitor-start induction-run motor produces a starting torque that is ____ that of the resistance-start induction-run motor.

Since both the start winding and the run winding of a capacitor-start capacitor-run motor remain energized at all times, the motor operates as a ____-phase motor.

To reverse the direction of a shaded-pole motor, you need to ____.

When connecting a dual voltage motor for high voltage, the leads must be connected in ____.

Because the start winding is wound with smaller wire and placed near the top of the stator, it will have ____ the run winding.

A thermistor is a device that exhibits a change of resistance with a change of ____.

The ____ functions as both a starting relay and an overload relay.

Capacitors are rated in ____.

When the leads of the compensating winding of a universal motor are shorted together, the connection is known as ____ compensation.

When a universal motor is operated on AC and the compensating winding is connected in series with the armature, it is known as ____ compensation.

The direction of rotation of a single-phase motor can be changed by reversing the connection of the ____.

In motors, the speed of the magnetic rotating field is called the ____ speed.