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

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

Phase angle to the amount of the current leads or lags

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

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

centrifugal switch

The coil of a potential relay has _________ resistance

high

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

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

energized

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