Inclass10SinglePhase Flashcards
Single-phase, 120 V/240 V power has four conductors, with a potential of 240 V between conductors A and B.
F
A single-phase motor does not have a method to create a rotating magnetic field.
F
The rotor of a single-phase motor is the same as in an induction squirrel-cage motor.
T
In order to start automatically, some single-phase motors use a capacitor winding.
F
The purpose in making motors for two voltages is to enable the same motor to be used with two different power line voltages.
T
To reverse the direction of most single-phase motors, all that is necessary is to switch the two start leads in the circuit.
T
A shaded-pole motor is an AC motor that uses a shaded stator pole for starting.
T
in a typical two-speed, split-phase motor, one run winding and two start windings are used to develop two separate speeds.
F
Typical applications of capacitor motors include refrigerators, air conditioners, air compressors, and some power tools.
T
The capacitors used to start motors are electrolytic capacitors.
T
Three types of capacitor motors are the capacitor shut-down motor, capacitor-run motor, and the capacitor start-and-run motor.
F
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.
F
A capacitor-run motor has the same starting torque as a capacitor-start motor.
F
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
b. run
Single-phase motors resist __________ without some method of creating a ___________ magnetic field. a. magnetization, strong
c. rotation, rotating b. stopping, fluctuating
d. rotation, stationary
c. rotation, rotating
Shaded-pole motors are commonly _________ HP or less and have low starting torque. a. 1/20 c. 10 b. 1/2 d. 20
a. 1/20
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
c. shaded pole
_________________ 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
b. speed
_________________ 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
c. inductive reactance
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
a. 75
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
a . poles
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
b. capacitor
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
d. capacitor start and run
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
b. two-speed, split phase
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
c. 60 - 80%
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
a. salient
A(n) ____________________ is a single turn of copper wire wrapped around part of the salient pole of a shaded-pole motor.
shading coil
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.
split-phase motor
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.
centrifugal switch
Reversing the __________________ is the standard method used in industry for reversing the direction of rotation of a single-phase motor.
start winding
The ___________________ motor is the most common type of capacitor motor.
capacitor-start
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.
rotor
In a typical _______________________ motor, the run winding is split into two sections.
dual voltage
A(n) ____________________ is constructed of many notched thin sheets (laminations) of steel to limit eddy currents in the stator.
stator core
A(n) ____________________ motor is also known as a permanent split-capacitor motor.
capacitor run
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.
auxiliary-winding
In a capacitor-run motor the addition of a second auxiliary winding creates a(n) ____________________-speed version of the motor.
Three
Capacitor start-and-run motors are typically used to run ____________________ and air compressors.
refrigerators
In a single-phase motor stator, the start winding is placed __________ mechanical degrees from the run windings
90
