Three-Phase Systems in Power Applications - General Questions (1)

Directions to Solve

Three-Phase Systems in Power Applications - General Questions

1.

In a -connected generator, all of the phase voltages are

A.	zero
B.	equal in magnitude
C.	one-third of total
D.	one-sixth of total

Answer: Option B

Explanation:

No answer description available for this question.

2.

In a Y-connected source feeding a -connected load,

A.	each phase of the load has one-third of the full line voltage across it
B.	each phase of the load has two-thirds of the full line voltage across it
C.	each phase of the load has the full line voltage across it
D.	each phase of the load has a voltage across it equal to √3

Answer: Option C

Explanation:

No answer description available for this question.

3.

The most common type of ac motor is the

A.	single-phase induction motor
B.	two-phase induction motor
C.	three-phase induction motor
D.	two-phase squirrel-cage motor

Answer: Option C

Explanation:

No answer description available for this question.

4.

In a Y-connected circuit, between each line voltage and the nearest phase voltage, there is a phase angle of

A.	0°
B.	30°
C.	60°
D.	120°

Answer: Option B

Explanation:

No answer description available for this question.

5.

A three-phase -connected generator is driving a balanced load such that each phase current is 12 A in magnitude. When I θ_a = 12 30° A, what are the polar expressions for the other phase currents?

A.	I θb = 12 150° A, I θc = 12–90° A
B.	I θb = 12∠120° A, I θc = 12∠30° A
C.	I θb = 12∠30° A, I θc = 12∠120° A
D.	I θb = 12∠90° A, I θc = 12∠90° A

Answer: Option A

Explanation:

No answer description available for this question.

6.

In a certain Y-Y system, the source phase currents each have a magnitude of 9 A. The magnitude of each load current for a balanced load condition is

A.	3 A
B.	6 A
C.	9 A
D.	27 A

Answer: Option C

Explanation:

No answer description available for this question.

7.

In a balanced three-phase load, each phase has

A.	an equal amount of power
B.	one-third of total power
C.	two-thirds of total power
D.	a power consumption equal to √3VL IL

Answer: Option A

Explanation:

No answer description available for this question.

8.

Polyphase generators produce simultaneous multiple sinusoidal voltages that are separated by

A.	certain constant phase angles
B.	certain constant frequencies
C.	certain constant voltages
D.	certain constant currents

Answer: Option A

Explanation:

No answer description available for this question.

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