Basic General Knowledge Questions and Answers Electrics - Set 04

G.K. Practice Test: Question Set - 04

1. If A.C is fed by mistake to a D.C motor, then the D.C motor will
    (A) Burn as the eddy currents in the field produces heat
    (B) Run at its normal speed
    (C) Run at a lower speed
    (D) Run continuously, but the sparking takes place at the brushes

2. The following motor is preferred for locomotives motor drives
    (A) A.C Series motor
    (B) Induction motor
    (C) D.C Series motor
    (D) Synchronous motor

3. Which of the following motors has high starting torque?
    (A) D.C shunt motor
    (B) Squirrel cage induction motor
    (C) D.C Series motor
    (D) A.C Series motor

4. In a D.C generator, following loss will be minimum
    (A) Copper loss
    (B) Iron loss
    (C) Friction loss
    (D) Shunt field copper loss

5. If the excitation to the field of the D.C motor is constant, then the torque developed in the motor is proportional to
    (A) Armature current
    (B) Field current
    (C) Speed
    (D) Magnetic flux

6. Eddy current loss in a D.C shunt generator is proportional to
    (A) Flux density
    (B) √(Flux density)
    (C) 1/ Flux density
    (D) (Flux density)²

7. The torque of a D.C series motor with increase in speed
    (A) Increases gradually
    (B) Decreases linearly
    (C) Remain constant
    (D) First decreases rapidly and then slowly

8. The function of the commutator in a D.C machine is
    (A) To change alternating current to a direct current
    (B) To improve commutation
    (C) To improve efficiency of motor
    (D) To change alternating voltage to direct voltage

9. The torque in induction motor is proportional to
    (A) Slip s
    (B) 1/s
    (C) s²
    (D) 1 - s

10. Which of the following motors is usually used in household refrigerator?
    (A) D.C shunt motor
    (B) Reluctance motor
    (C) Single phase induction motor (split phase start or induction run motor)
    (D) Synchronous motor

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