Motors And Controls Final Exam

Question 1

Are AC power source motors induction or conduction types?

Answer 1

(AC) has brushes

induction

Question 2

Are DC power source motors induction or conduction types?

Answer 2

Conduction

Question 3

Which electrical motor runs on either AC or DC?

Answer 3

Universal

Question 4

If the electrical current through the coil is reversed, what would happen to the produced magnetic field?

Answer 4

Reverse

Question 5

What are two types of motor operation on a magnetic motor starter can provide?

Answer 5

Start

Stop

Question 6

What advantages does a single-phase motor have over a three-phase motor?

Answer 6

Can be used where 3-phase can’t

Question 7

Which type of electric motors require start windings?

Answer 7

Single phase induction motor

Question 8

What is the advantages of installing the control circuit as a class defined power source circuit if possible?

Answer 8

Control circuit runs on a lower volatage for safety reasons

Question 9

How is a single-phase motor reversed?

Answer 9

Reverse start or the auxiliary, but not both

Question 10

How is a three-phase motor reversed?

Answer 10

Change any 3-phase comnection to the start winding

Question 11

What two functions do capacitors perform in a single-phase motors?

Answer 11

Start

Run

Question 12

Condition where the magnetic poles of the run winding will alternate between north and south at sychonous speed of the power supply but does not product rotation?

Answer 12

Locked rotor

Question 13

This is used to determince the amount of mechanicl work that can be performed?

Answer 13

Torque

Question 14

This is a measurement used to determine how much work is heing completed in a certain amount of time?

Answer 14

Power

Question 15

List the three types of relays that may be used to disconnect the start winding of single-phase motors when a centrifugal switch on the rotor shaft cannot br used?

Answer 15

Current relay
Potential relay
Solid state relay

Question 16

What components does a single-phase motor require that a three-phase motor does not?

Answer 16

Start and run capacitors

Question 17

Is the start winding a lower or hogher resistance than the main winding?

Answer 17

Higher

Question 18

Is the start winding a smaller or bigger gauge than thr main winding?

Answer 18

Smaller

Question 19

What are two purposes for run capacitors in the auxiliary winding?

Answer 19

Maintaining torque

Create a phase-shift between auxiliary winding

Question 20

What is the main limitation of shaded-pole motors?

Answer 20

Low starting torque and low efficiency

Question 21

Single phase induction motor both start and run reversed, what would happen to rotation?

Answer 21

Nothing

Question 22

Which electrical property is responsible for creatig magnetic flux?

Answer 22

Induction

Question 23

Why are induction motors so popular?

Answer 23

More reliable at a lower cost

Question 24

The terminals at the bottom of a motor starter are labeled what?

Answer 24

2 and 3

Question 25

Which circuit conductod gets landed on the top terminals of a motor stater?

Answer 25

L1, L2, and L3

Question 26

The overload contacts are wired in which circuit?

Answer 26

Between the starter and neutral leg of the control circuit

Question 27

Why does the moving contact of a relay sweep across the face of rhe stationary contact?

Answer 27

Mechanically clean

Question 28

Which unit has both controls circuit?

Answer 28

The contactor

Question 29

FLA ?

Answer 29

Full loaded amps

Question 30

LRA?

Answer 30

Locked rotor amps

Question 31

List two instances when a motor will be exposed to LRA?

Answer 31

at startup Low starting toque

Question 32

When reversing a single-phase motor what terminals are switched?

Answer 32

T5 and T8

Question 33

What are three winding configurations for DC motors?

Answer 33

Series Shunt Compound

Question 34

This winding has small number of turns?

Answer 34

Series

Question 35

This winding uses a strong flux to keep the armature locked in and requires the field to be powered first before the armature

Answer 35

Shunt winding

Question 36

DC motor that uses both series and shunt winding?

Answer 36

Compound winding

Question 37

What is nominal voltage?

Answer 37

Designed or figuration voltage