Notes

Question 1

Similar Triangles?

Answer 1

Will always have the same angles but may have different lengths

Question 2

Scalar has?

Answer 2

magnitude only

Question 3

Vector has?

Answer 3

both magnitude and direction

Question 4

Why do we use AC over DC for most of the electrical power?

Answer 4

It can be transformed, stepped up or down

Question 5

Faradays Law of electromagnetic induction?

Answer 5

Magnitude or voltage induced in a turn of wire is proportional to the rate of change of flux passing through the turn

Question 6

Eg represents?

Answer 6

Voltage generated in volts

Question 7

B (beta) represents?

Answer 7

flux density of the field in tesla

Question 8

I represents?

Answer 8

Active length

Question 9

Easiest and most common way to control generated voltage?

Answer 9

field rheostat in series

Question 10

Thumb represents?

Answer 10

Motion of conductor

Question 11

Pointer (second finger) represents?

Answer 11

direction of field (flux)

Question 12

Middle finger represents?

Answer 12

Direction of induced electron flow

Question 13

Source power is always ?

Answer 13

Positive to negative

Question 14

What is the “prime mover”?

Answer 14

Machine that supplies the mechanical energy to the alternator

Question 15

Name types of ways an alternator can be started?

Answer 15

Steam turbines, water turbines, windmills, combustion engines

Question 16

What parts of the alternator has voltage induced in it?

Answer 16

Armature

Question 17

Sine wave with 2 poles will produce _____ degrees electrical and _______ degrees mechanical?

Answer 17

360

360

Question 18

Sine wave with 4 poles will produce _______ degrees electrical and _________ mechanical?

Answer 18

720 electrical and 360 mechanical

Question 19

Alternating current?

Answer 19

changes in both magnitude and direction

Question 20

Cycle?

Answer 20

Distance from point on a waveform to where it begins repeating

Question 21

Alternation?

Answer 21

One cycle of a sin wave contains to alternations. (.5 of the sine wave)

Question 22

Period?

Answer 22

time it takes to complete one cycle

Question 23

Frequency?

Answer 23

Number of complete cycles that occur in one second

Question 24

formula for frequency?

Answer 24

f= I/p

Question 25

amplitude?

Answer 25

max height of the waveform above or below zero axis (PEAK)

Question 26

Peak value?

Answer 26

maximum positive or negative value of the waveform

Question 27

Peak to Peak value?

Answer 27

difference between positive or negative value of the waveform

Question 28

Instantaneous value?

Answer 28

Constantly changing

Question 29

Instantaneous values formula?

Answer 29

E= Epeak x Sin ō(theta)

Question 30

Average value of sin wave is ____?

Answer 30

Zero

Question 31

Average value of one alternation of a sins wave is?

Answer 31

0.637 or 63.7% of peak value

Question 32

effective value is?

Answer 32

.707 of peak

Question 33

Faradays Law?

Answer 33

Eg = B x I x v

Question 34

left hand rule for circles with arrows

arrows on top going right?

arrows on top going left?

Answer 34

right on top is a dot

left on top is an x

Question 35

How is flux density controlled?

Answer 35

magnitude of current

Question 36

what do brushes have?

Answer 36

limits on both current and voltage

Question 37

effective value of a sin wave is ?

Answer 37

.707 of the peak value (rms)

Question 38

In AC there are other properties that oppose the flow of current, they are?

Answer 38

P - pure ohmic resistance 
S - skin effect 
H - hysteresis loss
R - radiation loss 
E - eddy currents loss 
D - dielectric loss

Question 39

Frequency formula?

Answer 39

F = 1/P

or

P = 1/F

Question 40

Frequency/rotation formula?

Answer 40

F = PxN/120

Question 41

Faradays formula?

Answer 41

Eg = B x I x v

Question 42

Instantaneous formula?

Answer 42

E inst = Epeak x Sine angle