Alternating Current/Motors

Question 1

Extra low voltage is classified as

Answer 1

30v or less

Question 2

Low voltage is classified as

Answer 2

31v-750v

Question 3

High voltage is classified as

Answer 3

750v or more

Question 4

RMS stands for?

Answer 4

Root means square

Question 5

RMS is also known as?

Answer 5

effective value

Question 6

What does RMS measure?

Answer 6

value of the AC wave that indicates the same energy potential as an equivalent DC source

Question 7

What does it mean to be “out of phase”?

Answer 7

When voltage wave/current reach peak values and 0 values at different points in time

Question 8

What does it mean to be “in phase”

Answer 8

When voltage wave/current reach peak values at the same time

Question 9

What is a phase angle?

Answer 9

Difference in degrees between one phase and another

Question 10

Factors affecting inductance? (5)

Answer 10

1. Number of turns
2. coil diameter
3. length of coil
4. core material
5. winding coil layers

Question 11

Factors affecting capacitance? (2)

Answer 11

1. Area of plates: Larger plates = Increased capacitance
2. Distance between plates: Closer; increases capacitance. Further

Question 12

What does a “Henry” describe?

Answer 12

Amount of resistance in an inductive load

Question 13

What does “ICE” refer to when referencing capacitors?

Answer 13

Current in a capacity circuit slows voltage

Question 14

In a resistive circuit, current and voltage are _______ phase

Answer 14

IN

Question 15

In a inductive circuit, current ____ voltage by 90 degrees

Answer 15

lags

Question 16

In a capacitive circuit, current ______ voltage by 90 degrees

Answer 16

leads

Question 17

Transformers primary and secondary windings are not electrically connected. True or False?

Answer 17

True

Question 18

Three basic components of a transformer are?

Answer 18

Prim, Sec, Core

Question 19

The secondary winding on a transformer is opposite polarity of the primary. T or F?

Answer 19

True

Question 20

Name some transformer core materials?

Answer 20

Air
Iron
Soft iron
Laminated steel

Question 21

Name a few types of single phase transformers

Answer 21

control
tapped
isolation
auto
current
potential

Question 22

Name the three types of power transformers

Answer 22

1. Open Delta
2. Closed Delta
3. Wye (star)

Question 23

An open delta power transformer reads: (2)

Answer 23

240v
120v

Question 24

A closed delta power transformer reads: (3)

Answer 24

240v
208v
120v

Question 25

A Wye (star) power transformer reads

Answer 25

208v
120v

Question 26

Three main reasons for power loss in transformers?

Answer 26

1. Resistance in windings
2. Hysteresis
3. Eddy currents

Question 27

How to reduce eddy loss in transformer core?

Answer 27

Use laminated core

Question 28

What is Hysteresis?

Answer 28

heat losses due to friction between molecules

Question 29

What are eddy currents?

Answer 29

Losses due to current flow in core material

Question 30

Voltage imbalance may be within __%

Answer 30

2%

Question 31

Current imbalance may be within ___%

Answer 31

10%

Question 32

Short to ground is read as ____ or ___ resistance

Answer 32

low or no

Question 33

CSIR motor does not have a ______ capacitor and becomes a ____ motor when the potential relay drops out

Answer 33

start

PSC

Question 34

What is the acronym to remember when dealing with potential start relays?

Answer 34

5,2,1

Can She Run?

Question 35

Normally closed contacts on a potential relay are located between __ and __ contacts

Answer 35

1 and 2 contacts

Question 36

Locked rotor amps is __ times the RLA/FLA

Answer 36

6 times

Question 37

RLA/FLA is ___ of the LRA

Answer 37

1/6