Deck 2: Induction Motor Overview

Question 1

A method of graphically demonstrating the power factor relationship between energy and power, is with the power ____.

A)triangle
B)square
C)quadrant
D)grid

Answer 1

A

Question 2

The minimum torque developed from locked-rotor to breakdown torque is called ____ torque.

A)pull-up
B)breakdown
C)locked-rotator
D)full-load

Answer 2

A

Question 3

The highest current draw is at locked-rotor (zero RPM) speed for NEMA Design B motors, and does not start to drop off significantly until the rotor reaches ____ full-load speed.

A)70-75%
B)80-85%
C)90-95%
D)100%

Answer 3

B

Question 4

What is the label designation for the leads of the stator brought out to the conduit box?

A)T
B)C
C)V
D)A

Question 5

____ torque is a term used to describe when the rotor turns in jerks or increments rather than a smooth turning motion.

A)Cogging
B)Induction
C)Counterclockwise
D)Magnetic

Question 6

Any part of the motor that rotates is mounted to the ____.

A)shaft key
B)cooling fan
C)shaft
D)terminal

Question 7

The ____ holds all the parts of a motor together.

A)mounting base
B)motor housing
C)shaft
D)conduit box

Question 8

What are the two reasons why there is a thin layer of insulation on magnet wire?

Question 9

Rotors of induction motors are referred to as ____________________ rotors.

Question 10

When electrical energy is applied to a device that can convert it to another form of energy, such as an electric motor converting it to mechanical energy, it performs ____.

A)transfer
B)kinetic energy
C)energy
D)work

Question 11

____ is a turning force that determines what mechanical work may be performed.

A)Torque
B)Foot/pounds
C)Energy
D)Power

Question 12

The torque produced at full load speed that gives the rated horsepower output of the motor is called ____ torque.

A)pull-up
B)breakdown
C)locked-rotor
D)full-load

Question 13

The maximum torque the motor can develop, after having reached full operating speed at the rated voltage and frequency, before stalling (experiencing an abrupt drop in speed), is called ____ torque.

A)pull-up
B)breakdown
C)locked-rotor
D)full-load

Question 14

VARs stands for ____________________.

Question 15

The most common general purpose NEMA motor is ____.

A)Design A
B)Design B
C)Design C
D)Design D

Question 16

____ is the measurement of how much work is accomplished in a specific amount of time, with time being the differentiating focus.

A)Power
B)Torque
C)Work
D)Energy

Question 17

____________________ is defined as the capacity, or potential, to perform work.

Question 18

The torque that the motor develops at zero speed (rotor not turning) when the rated voltage and frequency are applied is called ____ torque.

A)pull-up
B)breakdown
C)locked-rotor
D)full-load

Question 19

Resistive loads are said to be ____________________, because voltage and current are always the same polarity, and are being used in the same proportion for all time points along the horizontal axis of wave forms.

Question 20

Molten ____________________ is poured through the laminations into the cavities designed to form rotor bars.

Question 21

Describe what power factor is and what a poor power factor means.