Electrical machine MCQ #4
1) The number of parallel path in a 8-pole duplex lap winding is equal to
(a) 4
(b) 8
(c) 16
(d) 32
2) The function of dummy coils in DC machines is to
(a) reduce armature reaction
(b) provide alternate flux
(c) reduce losses
(d) provide mechanical balancing
3) The armature of a D.C. generator is usually made of
(A) silicon steel.
(B) copper.
(C) non ferrous material.
(D) cast iron.
4) The rotor part of a DC machine carries
(a) armature winding
(b) field winding
(c) either field or armature winding
(d) none of the above
5) A D.C. generator works on the principle of
(A) Lenz’s law.
(B) self induction.
(C) ohm’s law.
(D) Faraday’s law of electromagnetic induction.
ANSWER:- | 1-C | 2-B | 3-A | 4-A | 5-D |
6) In a DC motor the direction of rotation is determined by
(a) Lenz law.
(b) Faraday Law.
(c) Fleming left hand rule.
(d) Fleming right hand rule
7) The armature resistance of the DC motor is nearly equal to
(a) 0.05 ohm.
(b) 0.5 ohm.
(c) 50 ohm.
(d) 105 ohm.
8) Universal motors are used in
(a) conveyor.
(b) food mixer.
(c) elevator.
(d) refrigerator.
9) When the motor speed of the stepper motor increases, the torque will
(a) increases.
(b) remain same.
(c) decrease.
(d) none of the above.
10) Which of the following special motor has rotor movement in discrete step?
(a) Stepper motor.
(b) Reluctance motor.
(c) Servo motor.
(d) Hysteresis motor.
ANSWER:- | 6-C | 7-B | 8-B | 9-C | 10-A |
11) The purpose of using starting winding in single phase induction motor is to
(a) improve voltage regulation.
(b) increase speed.
(c) developed starting torque.
(d) improve power factor.
12) Circle diagram of an induction motor can be used determine its
(a) power factor.
(b) efficiency.
(c) slip.
(d) all of the above.
13) In an induction motor, the air gap flux density is usually kept low in order to
(a) Improve voltage regulation.
(b) reduce losses.
(c) improve speed regulation.
(d) improve power factor.
14) The stator core of a three phase induction motor is laminated in order to reduced the
(a) hysteresis losses.
(b) eddy current losses.
(c) copper losses.
(d) all of the above.
15) Slip ring motor is preferred over squirrel cage induction motor where
(a) high starting torque is required.
(b) load torque is heavy.
(c) heavy pull out torque is required.
(d) all of the above.
ANSWER:- | 11-C | 12-D | 13-D | 14-B | 15-A |
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