3 Phase Induction Motor MCQ With Answer -3, these questions are important for Online AITT CBT Exam of Electrician First Year Trade, all questions are based on NIMI pattern (NSQF Level 5). This question is also important for other competitive exams like Technical Helper, RRB, ALP, Metro, Technician, JDVVNL, JVVNL, UPPCL etc.
3 Phase Induction Motor MCQ With Answer -3
1. Which is the most popular motor control circuit?
(A) speed control
(B) Stator Controller
(C) rotor controller
(D) Motor Starter Controller
Answer- (D)
2. The magnetizing current of the motor is more than that of the transformer because?
(A) The rotor grooves are opposite.
(B) efficiency decreases
(C) There is an air gap in the stator and rotor.
(D) The rotor is mounted on the bearing
Answer - (C)
3. Does the motor slip at the start?
(A) infinite
(B) zero
(C) unit
(D) half
Answer - (C)
4. The motor takes a high current in the beginning because?
(A) back emf is zero
(B) Normal voltage is given
(C) power factor is low
(D) Slip is more
Answer- (A)
5. What is the frequency of rotor emf in starting?
(A) same as supply frequency
(B) zero
(C) Half of the supply frequency
(D) double the supply frequency
Answer- (A)
6. Where do you use pole conversion method for moving?
(A) Both cage and slipping motor
(B) Cage induction motor
(C) slipping motor
(D) None of these
Answer (B)
7. Does winding always occur in the rotor?
(A) in two phases
(B) in one phase
(C) in three phases
(D) in any phase
Answer- (D)
8. When the starter of a motor is tripped due to low voltage, when can I restart the motor?
(A) the supply voltage returns to normal
(B) Reset button of overload should be pressed
(C) Supply should be 70 percent of normal voltage
(D) add motor to delta
Answer- (A)
9. What is the effect of loss of star delta starter?
(A) to generate high voltage
(B) get low starting torque
(C) Can not add external copy to it
(D) the motor takes a low current
Answer (B)
10. In an induction motor, the stator and rotor core are made of magnetized material because?
(A) make the motor strong
(B) to reduce the magnetizing current
(C) to reduce the price
(D) to keep resistance down
Answer (B)
11. If there are three cycles to be produced in a mechanical cycle, how many poles should be in the motor winding?
(A) two
(B) four
(C) three
(D) six
Answer- (D)
12. What energy does an electric motor provide?
(A) magnetic energy
(B) heat energy
(C) light energy
(D) kinetic energy
Answer- (D)
13. An automatic star delta starter has connectors?
(A) two
(B) three
(C) four
(D) five
Answer (B)
14. Over load relay is selected according to .............. Section?
(A) wading
(B) full weight
(C) Starting
(D) zero weight
Answer- (A)
15. What should be the minimum contact in a timer used in a star delta starter?
(A) two NO and one NC
(B) two NC and one NO
(C) two NO
(D) One NC and one NO
Answer- (D)
16. For the use of time relay, it is set in such a way that it can change the ........... connection?
(A) Star to Star
(B) Delta to Star
(C) Star to Delta
(D) None of these
Answer - (C)
17. The rotor of an induction motor cannot run at equal speed because?
(A) prevents air friction
(B) rotor torque becomes zero
(C) does not follow lenz's law
(D) the motor will become a synchronous motor
Answer (B)
18. Can the value of the starting torque in the sliding motor be high?
(A) Star Delta Starter
(B) in DOL starter
(C) in the rotor rheostat starter
(D) in an auto transformer starter
Answer - (C)
19. Can a wound rotor motor be identified rather than a cage induction motor?
(A) from six terminals
(B) From the direction of rotation
(C) slip ring
(D) by the size of the motor
Answer - (C)
20. Can the speed of a cage induction motor be controlled?
(A) by changing the supply voltage
(B) By changing the current
(C) By changing the supply frequency
(D) by adding resistance to the rotor circuit
Answer - (C)