@⇒ Polyphase Induction Motors ⇒ Electrical Engineering Multiple Choice Questions / Objective type questions, MCQ's, with question and answers, download free PDF, short cut notes, rapid fire notes, best theory

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Q1.	A 3-phase 440 V, 50 Hz induction motor has 4% slip. The frequency of rotor e.m.f. will be
A.	200 Hz [Wrong Answer]
B.	50 Hz [Wrong Answer]
C.	2 Hz [Correct Answer]
D.	0.2 Hz [Wrong Answer]
View Answer 70 -96 Explanation:- Answer : C Discuss it below : DJ Said on 2015-08-21 02:50:09 Rotor frequency = SF Click here for more comments


Q2.	The shaft, on which the rotor of an induction motor is mounted is made of
A.	high speed steel [Wrong Answer]
B.	chrome vanadium steel [Wrong Answer]
C.	cast-iron [Wrong Answer]
D.	mild steel [Correct Answer]
E.	aluminium [Wrong Answer]
View Answer 21 -3 Explanation:- Answer : D Discuss it below : Click here for more comments


Q3.	The direction of rotation of a 3-phase induction motor can be reversed by
A.	interchanging any two phases [Correct Answer]
B.	supplying low voltage [Wrong Answer]
C.	reducing load [Wrong Answer]
D.	reducing frequency [Wrong Answer]
View Answer 15 -4 Explanation:- Answer : A Discuss it below : Dinesh chauhan Said on 2018-03-20 01:29:47 nice Click here for more comments


Q4.	The starting torque of the slip ring induction motor can be increased by
A.	adding resistance to the stator [Wrong Answer]
B.	adding resistance to the rotor [Correct Answer]
C.	adding resistance to stator as well as the rotor [Wrong Answer]
D.	none of the above [Wrong Answer]
View Answer 13 -4 Explanation:- Answer : B Discuss it below : Click here for more comments


Q5.	A 3-phase induction motor is running at a load of the rated torque. What happens when one of the outer mains is interrupted while the motor is running ?
A.	The motor keeps on running and the current drawn does not change [Wrong Answer]
B.	The motor keeps on running but draws more current [Correct Answer]
C.	The motor stops immediately [Wrong Answer]
D.	The motor stops after a few seconds [Wrong Answer]
View Answer 12 -6 Explanation:- Answer : B Discuss it below : Click here for more comments

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