# Practice Test: Question Set - 01

**1. 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

**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

**3. 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

**4. In a ∆-connected source feeding a Y-connected load**

- (A) Each
phase voltage equals the difference of the corresponding load voltages

- (B) Each
phase voltage equals the corresponding load voltage

- (C) Each
phase voltage is one-third the corresponding load voltage

- (D) Each
phase voltage is 60° out of phase with the corresponding load voltage

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

- (A) True

- (B) False

**6. A simple two-phase generator consists of two conductive loops separated by 90°, rotating in a magnetic field.**

- (A) True

- (B) False

**7. 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

**8. A three-phase ∆-connected generator is driving a balanced load such that each phase current is 12 A in magnitude. When**

*I*θ*= 12 ∠30° A, what are the polar expressions for the other phase currents?*_{a}- (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

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

- (A) True

- (B) False

**10. In a Y-Y source/load configuration, the**

- (A) Phase
current, the line current, and the load current are all equal in each phase

- (B) Phase
current, the line current, and the load current are 120° out of phase

- (C) Phase
current and the line current are in phase, and both are 120° out of phase with
the load current

- (D) Line
current and the load current are in phase, and both are out of phase with the
phase current

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