GROL Power Sources and Distribution 2

Question 1

What is the power factor of a purely resistive AC circuit?

Accepted Answer

1.0 (voltage and current in phase)

Answer

In a purely resistive circuit, voltage and current are perfectly in phase, so the power factor equals 1.0.

Question 2

A transformer with a primary-to-secondary turns ratio of 1:2 connected to 120V AC will produce what secondary voltage?

Accepted Answer

240V, stepping up the voltage

Answer

A 1:2 turns ratio means the secondary has twice as many turns, doubling the voltage from 120V to 240V.

Question 3

What happens to capacitive reactance (Xc) as the frequency of the applied AC signal increases?

Accepted Answer

Xc decreases as frequency increases

Answer

Capacitive reactance Xc = 1/(2πfC), so reactance decreases as frequency increases.

Question 4

In a balanced three-phase power system, what is the phase angle difference between each of the three voltage waveforms?

Accepted Answer

120 degrees

Answer

In a three-phase system, the three voltage waveforms are equally spaced 120 degrees apart in the electrical cycle.

Question 5

What is the primary role of the neutral conductor in a single-phase 120/240V AC distribution system?

Accepted Answer

To carry return current and establish a stable voltage reference point

Answer

The neutral conductor carries return current from loads and is bonded to ground to provide a stable voltage reference.

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