Practice Test: Question Set - 03
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
2. 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
3. In a ∆-connected source driving a ∆-connected load, the
- (A) Load voltage
and line voltage are one-third the source voltage for a given phase
- (B) Load
voltage and line voltage are two-thirds the source voltage for a given phase
- (C) Load voltage
and line voltage cancel for a given phase
- (D) Load
voltage, line voltage, and source phase voltage are all equal for a given phase
4. A simple three-phase generator consists of three conductive loops separated by 120°.
- (A) True
- (B) False
5. The stator is the rotating assembly in a generator or motor.
- (A) True
- (B) False
6. In a three-phase system, when the loads are perfectly balanced, the neutral current is
- (A) Zero
- (B) One-third of
maximum
- (C) Two-thirds
of maximum
- (D) At maximum
7. 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
8. A balanced load is one in which all the impedances are equal.
- (A) True
- (B) False
9. A single-phase sinusoidal voltage of 120 V is connected to a 90 Ω load. Current in the circuit is
- (A) 13.3 mA
- (B) 133 mA
- (C) 1.33 A
- (D) 6.2 A
10. A constant load power means a uniform conversion of
- (A) Mechanical
to electrical energy
- (B) Electrical
to mechanical energy
- (C) Current to
voltage
- (D) Voltage to
current
11. 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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