Three Phase Systems In Power Applications MCQ Questions & Answers

1.
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 $$\sqrt 3 $$

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2.
The stator is the rotating assembly in a generator or motor.

A. True

B. False

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3.
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°

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4.
Compare the total copper cross sections in terms of current-carrying capacity for a single-phase and a three-phase 120 V system with effective load resistance of 15 Ω.

A. Single-phase 32 A; three-phase 16 A

B. Single-phase 16 A; three-phase 8 A

C. Single-phase 8 A; three-phase 4 A

D. Single-phase 16 A; three-phase 0 A

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5.
An alternator is an electromechanical ac generator.

A. True

B. False

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6.
In a ∆-connected generator, there is a 120° difference between each line current and the nearest phase current.

A. True

B. False

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7.
In a Y-connected generator, there is a 120° difference between each line voltage and the nearest phase voltage.

A. True

B. False

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8.
Power is measured in a three-phase load by using an ammeter.

A. True

B. False

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9.
A two-phase generator is connected to two 90 Ω load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?

A. 1.33 A

B. 1.88 A

C. 2.66 A

D. 1.77 A

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10.
A three-phase generator is connected to three 90 Ω load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?

A. 0 A

B. 1.33 A

C. 3.99 A

D. 2.66 A

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Three Phase Systems In Power Applications MCQ Questions & Answers | Electrical Engineering

1. In a Y-connected source feeding a ∆-connected load,

Answer & Solution

2. The stator is the rotating assembly in a generator or motor.

Answer & Solution

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

Answer & Solution

4. Compare the total copper cross sections in terms of current-carrying capacity for a single-phase and a three-phase 120 V system with effective load resistance of 15 Ω.

Answer & Solution

5. An alternator is an electromechanical ac generator.

Answer & Solution

6. In a ∆-connected generator, there is a 120° difference between each line current and the nearest phase current.

Answer & Solution

7. In a Y-connected generator, there is a 120° difference between each line voltage and the nearest phase voltage.

Answer & Solution

8. Power is measured in a three-phase load by using an ammeter.

Answer & Solution

9. A two-phase generator is connected to two 90 Ω load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?

Answer & Solution

10. A three-phase generator is connected to three 90 Ω load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?

Answer & Solution

1.
In a Y-connected source feeding a ∆-connected load,

2.
The stator is the rotating assembly in a generator or motor.

3.
In a Y-connected circuit, between each line voltage and the nearest phase voltage, there is a phase angle of

4.
Compare the total copper cross sections in terms of current-carrying capacity for a single-phase and a three-phase 120 V system with effective load resistance of 15 Ω.

5.
An alternator is an electromechanical ac generator.

6.
In a ∆-connected generator, there is a 120° difference between each line current and the nearest phase current.

7.
In a Y-connected generator, there is a 120° difference between each line voltage and the nearest phase voltage.

8.
Power is measured in a three-phase load by using an ammeter.

9.
A two-phase generator is connected to two 90 Ω load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?

10.
A three-phase generator is connected to three 90 Ω load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?