Quiz 17

T/F: The centrifugal switch mounted on the shaft of a split-phase motor has a normally closed contact

True

A motor's speed is determined by _________.

number of motor poles

A split-phase has a _______ winding and a __________ winding

start, run

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

Larger size wire, drop to much voltage

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

Space thermostat

Start windings are placed _______ with the run winding

slightly out of phase

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

variable resistor

When a capacitor start induction run (CSIR) motor is running 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)

5 microfarads

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

Capacitor start, induction run (CSIR)

T/F: The contact(s) in a current type starting relay are normally closed

False

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

False

T/F: In order to change the direction of the rotation of a plot-phase motor, the technician must change the direction of current flow through the start winding.

True

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

True

T/F: The contact(s) in a potential type starting relay are normally closed.

True

T/F: The heavier the load on an operating motor, the greater the amount of slip.

True

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

True

T/F: The resistance of the windings in a three phase motor are all equal

True

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

greater starting torque

The shaded pole motor _________.

has little starting torque

The start windings have _______.

more turns that the run windings

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

stator

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

rotor

A permanent split-capacitor motor has a _________.

run capacitor only

Three phase motors have _________.

run windings only

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)

25 microfarads

T/F: A Capacitor start capacitor run (CSCR) motor is wired with a potential relay will have the start winding energized when the relay's contacts open.

True

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

current in the run winding

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

current relay

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

refrigerant gas

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

split

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

squirrel phase

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

terminal 5

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

Phase angle to the amount of the current leads or lags

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

centrifugal switch

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

energized

The coil of a potential relay has _________ resistance

high