G.K. Practice Test: Question Set - 05
1. The maximum temperature permitted for class A insulation is
- (A) 180 °C
- (B) 105 °C
- (C) 120 °C
- (D) 155 °C
2. The torque in the case of a wound rotor induction motor
- (A) Increases
as rotor resistance is increased
- (B) Decreases
as rotor resistance is increased
- (C) Remains
unaffected by increase/decrease of rotor resistance
- (D) Is
maximum when rotor is shorted
3. For hoist and cranes which motor should be selected
- (A) 3 phase induction
motor
- (B) Synchronous
motor
- (C) D.C series
motor
- (D) D.C shunt
motor
4. The power output of induction motor will be maximum when
- (A) The
equivalent load resistance is equal to the standstill reactance of the motor
- (B) The
equivalent load resistance is equal to the resistance of the motor
- (C) The
equivalent load resistance is equal to the standstill leakage impedance of the
motor
- (D) The slip is
zero
5. The speed of induction motor is
- (A) Synchronous
speed
- (B) Synchronous
speed × slip
- (C) Synchronous
speed/(1- slip)
- (D) Synchronous
speed × (1- slip)
6. Which of the following motors has high starting torque?
- (A) A.C motor
- (B) Induction
motor
- (C) Synchronous
motor
- (D) D.C series
motor
7. The starting torque of the slip ring induction motor is increased by
- (A) Adding
external resistance to the rotor
- (B) Adding the
external inductance to the rotor
- (C) Adding
both external resistance and inductance to the rotor
- (D) Adding
external capacitance to the rotor
8. An under-excited synchronous motor draws current at
- (A) Unity power
factor (p.f)
- (B) Leading p.f
- (C) Lagging p.f
- (D) Leading/lagging
depending on the underload/overload
9. The torque developed by an induction motor corresponding to zero slip is equal to
- (A) Maximum
- (B) Full rated
capacity
- (C) Zero
- (D) Minimum
10. Which of the following motors is most frequently used in industries?
- (A) Synchronous
motor
- (B) Commutator
motor
- (C) Single phase
A.C motor
- (D) 3 phase
induction motor
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