Inclass10SinglePhase

Question 1

Single-phase, 120 V/240 V power has four conductors, with a potential of 240 V between conductors A and B.

Answer 1

F

Question 2

A single-phase motor does not have a method to create a rotating magnetic field.

Answer 2

F

Question 3

The rotor of a single-phase motor is the same as in an induction squirrel-cage motor.

Answer 3

T

Question 4

In order to start automatically, some single-phase motors use a capacitor winding.

Answer 4

F

Question 5

The purpose in making motors for two voltages is to enable the same motor to be used with two different power line voltages.

Answer 5

T

Question 6

To reverse the direction of most single-phase motors, all that is necessary is to switch the two start leads in the circuit.

Answer 6

T

Question 7

A shaded-pole motor is an AC motor that uses a shaded stator pole for starting.

Answer 7

T

Question 8

in a typical two-speed, split-phase motor, one run winding and two start windings are used to develop two separate speeds.

Answer 8

F

Question 9

Typical applications of capacitor motors include refrigerators, air conditioners, air compressors, and some power tools.

Answer 9

T

Question 10

The capacitors used to start motors are electrolytic capacitors.

Answer 10

T

Question 11

Three types of capacitor motors are the capacitor shut-down motor, capacitor-run motor, and the capacitor start-and-run motor.

Answer 11

F

Question 12

Although a capacitor-start motor develops less starting torque than a split-phase motor, both motor types are the same when running because the capacitor and start windings are removed from the circuit when the motor comes up to speed.

Answer 12

F

Question 13

A capacitor-run motor has the same starting torque as a capacitor-start motor.

Answer 13

F

Question 14

In many cases, a single-phase motor is constructed with both a start and a ________ winding in the stator.
a. stop b. run c. amortisseur d. brake

Answer 14

b. run

Question 15

Single-phase motors resist __________ without some method of creating a ___________ magnetic field. a. magnetization, strong
c. rotation, rotating b. stopping, fluctuating
d. rotation, stationary

Answer 15

c. rotation, rotating

Question 16

Shaded-pole motors are commonly _________ HP or less and have low starting torque. a. 1/20 c. 10 b. 1/2 d. 20

Answer 16

a. 1/20

Question 17

The function of the ____________ is to delay the magnetic flux in the area of the pole that is shaded. a. salient pole c. shaded pole b. slim shady d. slip-ring

Answer 17

c. shaded pole

Question 18

_________________ control of shaded-pole motors is accomplished by adding windings in series with the main winding. a. Reverse speed c. Torque b. Speed d. Overload

Answer 18

b. speed

Question 19

_________________ is the opposition to the flow of AC in a circuit due to inductance a. Flux density c. Inductive reactance b. Capacitive reactance d. Magnetic flux

Answer 19

c. inductive reactance

Question 20

When the motor reaches approximately _________ % of full speed, the centrifugal switch opens, disconnecting the start winding from the circuit. a. 75 c. 50 b. 100 d. 95

Answer 20

a. 75

Question 21

The speed at which a split-phase motor runs is determined by the number of _______________ in the motor and the frequency of the supply voltage a. poles c. rotor laminations b. windings d. stator laminations

Answer 21

a . poles

Question 22

A __________________ motor is a single-phase motor with a capacitor connected in series with the start windings to produce phase displacement in the start winding. a. capacitive c. split-phase b. capacitor d. brushless

Answer 22

b. capacitor

Question 23

A _______________________ motor has two capacitors in parallel with each other and both in series with the start winding. a. capacitor run c. split-phase b. brushless d. capacitor start-and-run

Answer 23

d. capacitor start and run

Question 24

A ______________________________ motor is commonly wound to run on either six or eight poles. a. multispeed, single-phase c. single-speed, split-phase b. two-speed, split-phase d. multispeed, three-phase

Answer 24

b. two-speed, split phase

Question 25

A capacitor-start motor operates much the same as a split-phase motor, in that it uses a centrifugal switch that opens at approximately _____ % to _____ % of full-load speed. a. 20, 40 c. 60, 80 b. 40, 60 d. 80, 100

Answer 25

c. 60 - 80%

Question 26

For a shaded-pole motor, the stator has two or more _________________ poles that are divided into parts a. salient b. shaded c. rotor d. magnetic

Answer 26

a. salient

Question 27

A(n) ____________________ is a single turn of copper wire wrapped around part of the salient pole of a shaded-pole motor.

Answer 27

shading coil

Question 28

A(n) ____________________ is a single-phase AC motor that includes a run winding and a resistive start winding that creates a phase-shift for starting.

Answer 28

split-phase motor

Question 29

A(n) ____________________ is a switch that opens to disconnect the start winding when the rotor reaches a certain preset speed and reconnects the start winding when the speed falls below a preset value.

Answer 29

centrifugal switch

Question 30

Reversing the __________________ is the standard method used in industry for reversing the direction of rotation of a single-phase motor.

Answer 30

start winding

Question 31

The ___________________ motor is the most common type of capacitor motor.

Answer 31

capacitor-start

Question 32

A(n) ______________________ is the rotating, moving part of a motor, consisting of a core and windings, that converts the rotating magnetic field of the stator into the torque that rotates the shaft.

Answer 32

rotor

Question 33

In a typical _______________________ motor, the run winding is split into two sections.

Answer 33

dual voltage

Question 34

A(n) ____________________ is constructed of many notched thin sheets (laminations) of steel to limit eddy currents in the stator.

Answer 34

stator core

Question 35

A(n) ____________________ motor is also known as a permanent split-capacitor motor.

Answer 35

capacitor run

Question 36

Capacitor-run motors are available as two- or three-speed motors with the addition of _____________________ that are placed in series with either the start or the run windings.

Answer 36

auxiliary-winding

Question 37

In a capacitor-run motor the addition of a second auxiliary winding creates a(n) ____________________-speed version of the motor.

Answer 37

Three

Question 38

Capacitor start-and-run motors are typically used to run ____________________ and air compressors.

Answer 38

refrigerators

Question 39

In a single-phase motor stator, the start winding is placed __________ mechanical degrees from the run windings

Answer 39

90