Deck 9: Components for Electric Motors

Question 1

The starting amperage of an electric motor is usually stated as the ____________________.

Answer 1

locked rotor amperage (LRA),locked rotor amperage,LRA

Question 2

The running amperage of an electric motor is usually stated as the full-load amperage.

Answer 2

True

Question 3

What are the two basic types of motor drives used today?

Answer 3

There are two basic driving devices: direct drive and belt and pulley drive.

Question 4

Ball bearings are designed with an inner and an outer ring, which enclose the balls by use of a(n) ____________________.

Question 5

By using two pulleys and connecting them with a(n) ____________________, rotation can be transferred from the motor to the device.

Question 6

The advancement of solid-state controls has produced another type of current-sensitive relay, a PTC starting switch.

Question 7

The back electromotive force produced by the starting winding of a motor is not the controlling factor of a potential relay.

Question 8

The potential relay is easy to troubleshoot because only two parts of the relay must be checked.

Question 9

The two types of bearings used in the heating, cooling, and refrigeration industry are ____________________ bearings and sleeve bearings.

Question 10

The current relay is built much like a solenoid, with copper wire wrapped around a steel hollow core holding a steel plunger.

Question 11

The back electromotive force is the amount of voltage produced in the starting winding of a motor.

Question 12

The ____________________ is gaining popularity because it can be adapted easily to most any compressor.

Question 13

What are the three types of starting relays used on single-phase hermetic motors ?

Question 14

A(n) __________________ is that part of a rotating electric device that allows free movement.

Question 15

On all electric motors, the starting amperage is less than the running amperage because the rotor is stationary on startup.

Question 16

Describe the three ways in which ball bearings are lubricated and how often each should be done.

Question 17

Single-phase motors, with the exception of the permanent split-capacitor motor, must have some means of dropping the starting winding out of the circuit.

Question 18

What should be done for a permanent split-capacitor hermetic motor that is experiencing difficulty starting?

Question 19

____________________ methods require that a device turn with the same revolutions per minute as the motor.

Question 20

In an open-type motor, dropping the starting winding out of the circuit is accomplished by a centrifugal switch mounted on the motor that opens once the motor has reached 35% of its full speed.