Practice Test: Question Set - 03
1. As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for
- (A) Fans
- (B) Blowers
- (C) Sound equipment
- (D) Mixer grinders
2. The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it
- (A) Improves the efficiency
- (B) Helps the rotor teeth to remain under the stator
teeth
- (C) Helps in reducing the tendency of the rotor
teeth to remain under the stator teeth
- (D) Improves the power factor
3. Most of the fractional horsepower motors have either
- (A) Hard and annealed bearings
- (B) Ball or roller bearings
- (C) Soft and porous bearings
- (D) Plain or sleeve bearings
4. The capacitors used in single-phase capacitor motors have no
- (A) Voltage rating
- (B) Dielectric medium
- (C) Polarity marking
- (D) Definite value
5. Which of the following statements regarding single-phase induction motors correct?
- (A) It requires only one winding
- (B) It can rotate in one direction only
- (C) It is self-starting
- (D) It is not self-starting
6. If the capacitor of a single-phase motor is short-circuited
- (A) The motor will not start
- (B) The motor will run
- (C) The motor will run in reverse direction
- (D) The motor will run in the same direction at
reduced r.p.m.
7. A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will
- (A) Start and then stop
- (B) Start and run slowly
- (C) Start and run at rated speed
- (D) Not start at all
8. For which of the applications a reluctance motor is preferred?
- (A) Electric shavers
- (B) Refrigerators
- (C) Signaling and timing devices
- (D) Lifts and hoists
9. Which of the following motors has highest starting torque?
- (A) Repulsion motor
- (B) Shaped pole motor
- (C) Capacitor-start motor
- (D) Split-phase motor
10. The rotor of a hysteresis motor is made of
- (A) Aluminium
- (B) Cast iron
- (C) Chrome steel
- (D) Copper
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