Deck 17: Types of Electric Motors

Question 1

A split-phase has a ____ winding and a ____ winding.

A) start, run
B) start, common
C) common, run
D) run, common

Answer 1

A

Question 2

When a general duty split-phase motor reaches approximately 75% of its operating speed, the start winding is de-energized by a ____.

A) circuit board
B) capacitor
C) centrifugal switch
D) dual voltage switch

Answer 2

C

Question 3

A permanent split capacitor (PSC) motor that is running and up to speed will have the start winding ____.

A) energized
B) de-energized
C) in series with the run winding
D) removed from the circuit

Answer 3

A

Question 4

A current magnetic relay opens and closes its contacts based on the ____.

A) current in the start winding
B) voltage across the start winding
C) voltage across the run winding
D) current in the run winding

Question 5

The positive temperature coefficient resistor start device is a type of ____.

A) capacitor
B) variable resistor
C) switching device
D) diode

Question 6

When a Capacitor Start, Capacitor Run (CSCR) motor initially starts, what is the total capacitance acting on the motor? (Assume the run capacitor is 5 microfarads and the start capacitor is 20 microfarads, if present.)

A) 4 microfarads
B) 5 microfarads
C) 20 microfarads
D) 25 microfarads

Question 7

The starting device usually used on single phase, fractional horsepower motors requiring low starting torque is the ____.

A) potential relay
B) current relay
C) centrifugal switch
D) differential relay

Question 8

A permanent split-capacitor motor has a ____.

A) start and run capacitor
B) start capacitor only
C) run capacitor only
D) split phase capacitor

Question 9

Three phase motors have ____.

A) three start and three run windings for each phase
B) one start and one run winding for each phase
C) run windings only
D) a start switch in each phase circuit

Question 10

A motor's speed is determined by ____.

A) size
B) voltage
C) amperage
D) number of motor poles

Question 11

The magnetic fields generated in the rotor and stator of a motor causes the rotor to be pushed around the shaft.

Question 12

When a Capacitor Start Induction Run (CSIR) motor is running and up to speed, what is the total capacitance acting on the motor? (Assume the run capacitor is 5 microfarads and the start capacitor is 20 microfarads, if present.)

A) 4 microfarads
B) 5 microfarads
C) 20 microfarads
D) 25 microfarads

Question 13

The centrifugal switch mounted on the shaft of a split-phase motor has a normally closed contact.

Question 14

A split-phase motor that has a current relay and a start capacitor is called a(n) ____ motor.

A) Capacitor Start, Capacitor Run (CSCR)
B) Capacitor Start, Induction Run (CSIR)
C) Induction Start, Induction Run (ISIR)
D) Permanent Split Capacitor (PSC)

Question 15

In order to change the direction of rotation of a split-phase motor, the technician must change the direction of current flow through the start winding.

Question 16

The heavier the load on an operating motor, the greater the amount of slip.

Question 17

Capacitors wired in series with the starting winding provide a(n) ____.

A) longer starting time
B) greater starting torque
C) aid in starting three phase motors
D) more efficient operation at full load speed

Question 18

The shaded pole motor ____.

A) has little starting torque
B) has excessive starting torque
C) has greater efficiency than most split-phase motors
D) will start against a heavy starting load

Question 19

The start windings have ____.

A) fewer turns than the run windings
B) more turns than the run windings
C) the same number of turns as the run windings
D) larger diameter wire than the run windings

Question 20

Start windings are placed ____ with the run windings.

A) 180 degrees out of phase
B) in phase
C) slightly out of phase
D) in series

Question 21

The ______________ is a winding that, when energized, will generate a magnetic field as there will be current flowing through it.

Question 22

The coil of a potential relay has ____________________ resistance.

Question 23

The contact(s) in a potential type starting relay are normally closed.

Question 24

Once the start winding and the start capacitor have been removed for the circuit, the motor will continue to operate with only the run winding energized.

Question 25

The resistances of the windings in a three phase motor are all equal.

Question 26

When not air cooled, the heat generated by the motor in a hermetic motor-compressor assembly is removed by what?

Question 27

What is meant by the "phase angle" in an alternating current circuit?

Question 28

The difference between synchronous speed and full load speed is called ____________________.

Question 29

The windings of the relay coil in a current relay has very low resistance. Why?

Question 30

On a potential relay, the coil is connected between terminals 2 and ____________________.

Question 31

The contact(s) in a current type starting relay are normally closed.

Question 32

A Capacitor Start Capacitor Run (CSCR) motor that is wired with a potential relay will have the start winding energized when the relay's contacts open.

Question 33

By what means does a two speed compressor motor accomplish the speed change?

Question 34

The rotating portion of an electric motor is called the ____________________.

Question 35

The microfarad rating of the run capacitor is much lower than that of the start capacitor for any given motor application.

Question 36

A motor that has copper bars in the rotor is classified as a(n) ____________________ type.