A

Question 1

What type of protection does a 3 point starter provide

Answer 1

No field or loss of field protection

Question 2

What type of compounding provides constant voltage and speed

Answer 2

Flat compounded

Question 3

When resistance is removed from a dc motor what limits current?

Answer 3

Counter emf

Question 4

What does a self excited machine depend on to start

Answer 4

Residual magnetism

Question 5

How can we reverse the rotational direction of a machine

Answer 5

Swapping armature connections A2 AND A1

Question 6

What does a field winding create for a dc machine?

Answer 6

North and south magnetic poles at the pole pieces

Question 7

What is an advantage of a separately excited dc machine

Answer 7

Voltage and speed control

Question 8

Type of wound armature that has its windings connected in parallel

Answer 8

Lap wound

Question 9

Name the compound type for the question:

A differential short shunt has its full load voltage less than its no load voltage

A: cumulative
B:over
C:flat
D:under

Answer 9

Under compounded

Question 10

What is the commutator constructed of

Answer 10

Copper bars and mica insulation between them

Question 11

What purpose does the series field rheostat provide

Answer 11

It controls compounding

Question 12

What do we call the armature windings position in which the windings are parallel to the flux lines and no voltage is being induced

Answer 12

The neutral plane

Question 13

Protective device connected in series with shunt field in most compound generators

Answer 13

Field loss relay

Question 14

What type of manual starter provides greater ability to control speed

A; 3 point
Or
B: 4 point

Answer 14

4 point starter

Question 15

What component rides against the commutator segments and connect the armature to the external circuit of a dc generator
A:brushes
B:terminal leads
C:field windings
D:stator

Answer 15

A:Brushes

Question 16

When resistance is removed from the shunt field winding circuit what happens to the magnetic field?

A: collapse
B: decrease
C: stay the same
D: increase

Answer 16

D: increase

Question 17

If resistance was added to the shunt field winding circuit of a dc shunt motor what happens to motor speed

A:becomes easier to control
B:becomes uncontrolled
C:speeds up
D:slows

Answer 17

C: speeds up

Question 18

What type of compounding occurs when a cumulative long shunt compound motors full load speed is greater than no load speed

A:under
B:flat
C; over
D: memory

Answer 18

C: over

Question 19

What happens to CEMF generated as load is added to a series motor

A:decreases
B:reverses
C:splits
D:cemf increase

Answer 19

A:decreases (this is because cemf is directly proportional to speed)

Question 20

Main dis advantage to a three point starter

A:relies on a mechanical force
B:sloppy starts
C:loss of speed control

Answer 20

C: loss of speed control

Question 21

Best way to slow or stop a dc motor under normal operation

Answer 21

Dynamic breaking with mechanical breaking

Question 22

What is the function of the shunt field rheostat on a shunt motor

Answer 22

Speed control

Question 23

What components hold the brushes and maintain even pressure

Answer 23

Brush holders and springs

Question 24

What are the two types of bearings

Answer 24

Ball and sleeve, roller

Question 25

What component allows the commutator to freely rotate

Answer 25

Bearings

Question 26

Name the 3 factors that determine strength of electro magnet

Answer 26

Core material Amount of current Turns of wire

Question 27

What component of a dc generator turns ac to dc

Answer 27

Commutator

Question 28

What compound motor has field windings that aid each other to produce magnetism A:counter B:flat C:cumulative D:over

Answer 28

C:cumulative

Question 29

What is the name of the force that causes a motor to rotate? A:cemf B:Lorentz force C:speed D:torque

Answer 29

B:Lorentz force

Question 30

If we add more turns of wire in an armature coil will the CEMF increase or decrease?

Answer 30

INCREASE

Question 31

Name 2 industrial applications for a differential generator would be used Select 2 of the following options A:mining B: electroplating C:crane operation D:welding E: laser engraving

Answer 31

B: electroplating D: welding

Question 32

What windings are embedded in slots or holes in the main poles A:compensating windings B:shunt windings C:field windings D:commutating windings

Answer 32

A: compensating windings

Question 33

When starting a motor, what % shall FLA be limited to?

Answer 33

150%

Question 34

What type of motor is used when constant or adjustable speed is necessary A:current limiting B:shunt C: flat compounded D: over compounded

Answer 34

B: shunt

Question 35

What causes the shift of the neutral plane in a motor under load A:armature reaction B:cemf C:unstable brush positioning D: counter torque

Answer 35

A: armature reaction

Question 36

Where are magnetic flux lines most dense?

Answer 36

At the poles

Question 37

Four main components of an armature assembly

Answer 37

Shaft, iron core, commutator, armature windings

Question 38

What’re the 3 factors that determine output of generators?

Answer 38

# of loops on armature windings, speed of rotation, strength of magnetic field

Question 39

3 ways armature reaction can be corrected

Answer 39

Rotating brushes, add interpoles with commutating windings, compensating windings

Question 40

What are the windings wrapped around the interpoles called? A:series windings B:compensating windings C: shunt windings D: commutating windings

Answer 40

D: commutating windings

Question 41

What happens to torque of a motor when load is increased. A:increase B: decrease

Answer 41

A: increase

Question 42

What type of compound motor has winding that oppose each other in production of magnetism A:differential B:over C:lap D: under

Answer 42

A: differential

Question 43

What type of armature windings provides high and low voltage protection? A:frog B:wave C:lap

Answer 43

B: wave

Question 44

In a compound motor there are 2 ways in which the shunt winding can be connected to the armature and series windings What’re the names

Answer 44

Long, short shunts

Question 45

What type of generator is considered a constant voltage generator? Hint: there’s 2 ones a generator type ones a compound type

Answer 45

Shunt generator, flat compounded

Question 46

If current in a shunt field of a large compound motor drops below a certain level what device protects and disconnects power to the armature

Answer 46

Field loss relay

Question 47

3 most common methods of auto starting a motor?

Answer 47

CEMF, Current limiting, Time delay