Circuits

Question 1

100% inductive load

Answer 1

100% reactive power, no real power
Current and voltage are out of phase by 90 degrees
The ratio of real power to apparent power will be equal to 0

Question 2

Power factor of 0

Answer 2

100% reactive power
Inverse cosine of 0 = 90 degrees
Means the current and voltage are out of phase by 90 degrees

Question 3

Power factor of 1

Answer 3

100% real power
Means the current and voltage are in phase

Question 4

Power flow for a lagging power factor

Answer 4

Lagging power factor consumes reactive power
True of motors and inductive loads that require reactive power to generate a magnetic field

Question 5

Power flow of a leading power factor

Answer 5

Leading power factor produces reactive power
True of capacitors

Question 6

Power factor

Answer 6

Ratio of real power and apparent power
It is equal to the inverse cosine of the angle between the current and voltage

Question 7

Z actual motor

Answer 7

(V motor) ^2 / S motor

V = voltage (V)
S = power (VA)

Question 8

Symmetrical components notation

Answer 8

Positive = 1
Negative = 2
Zero = 0

Question 9

Symmetrical components - phase equations

Answer 9

IA = IA1 + IA2 + IA0

IB = IB1 + IB2 + IB0

IC = IC1 + IC2 + IC0

Question 10

Zero sequence components equations

Answer 10

IA0 = IB0 = IC0 = (IA + IB + IC) / 3

Question 11

Positive sequence component equation

Answer 11

IA1 = (IA + aIB + a^2IC) / 3

Question 12

Negative sequence components equation

Answer 12

IA2 = (IA + a^2IB + aIC) / 3