Practice Test: Question Set - 02
1. Reduced voltage starter can be used with
- (A) Slip ring motor only but not with squirrel cage
induction motor
- (B) Squirrel cage induction motor only but not with
slip ring motor
- (C) Squirrel cage as well as slip ring induction
motor
- (D) None of the above
2. Insertion of resistance in the stator of an induction motor
- (A) Increases the load torque
- (B) Decreases the starting torque
- (C) Increases the starting torque
- (D) None of the above
3. The injected e.m.f. in the rotor of induction motor must have
- (A) Zero frequency
- (B) The same frequency as the slip frequency
- (C) The same phase as the rotor e.m.f.
- (D) High value for the satisfactory speed control
4. Star-delta starting of motors is not possible in case of
- (A) Single phase motors
- (B) Variable speed motors
- (C) Low horse power motors
- (D) High speed motors
5. Which of the following component is usually fabricated out of silicon steel?
- (A) Bearings
- (B) Shaft
- (C) Stator core
- (D) None of the above
6. In three-phase squirrel-cage induction motors
- (A) Rotor conductor ends are short-circuited through
slip rings
- (B) Rotor conductors are short-circuited through end
rings
- (C) Rotor conductors are kept open
- (D) Rotor conductors are connected to insulation
7. In an induction motor the relationship between stator slots and rotor slots is that
- (A) Stator slots are equal to rotor slots
- (B) Stator slots are exact multiple of rotor
slots
- (C) Stator slots are not exact multiple of rotor
slots
- (D) None of the above
8. The starting torque of a 3 phase squirrel cage induction motor is
- (A) Twice the full load torque
- (B) 1.5 times the full load torque
- (C) Equal to full load torque
- (D) Any of the above
9. The stating torque of the slip ring induction motor can be increased by adding
- (A) External inductance to the rotor
- (B) External resistance to the rotor
- (C) External capacitance to the rotor
- (D) Both resistance and inductance to rotor
10. In an induction motor if air-gap is increased
- (A) The power factor will be low
- (B) Windage losses will be more
- (C) Bearing friction will reduce
- (D) Copper loss will reduce in an induction
motor
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