Three Phase Induction Motor Electrical Engineering MCQ Questions Answers
A three-phase induction motor is a fundamental and widely used electrical machine in various industrial applications. Its robust design, simple construction, and reliability make it a cornerstone of modern engineering. If you’re preparing for an examination or looking to enhance your knowledge about three-phase induction motors, this set of Multiple Choice Questions (MCQs) and their corresponding answers will help you test and expand your understanding.
1) The advantage of would rotor motor is that ……….
a) it is inexpensive
b) it requires less maintenance
c) external resistance can be inserted in the rotor circuit
d) none of the above
2)The full-load slip of a 3-phase induction motor ranges from ………
a) 10% to 20%
b) 20% to 30%
c) 2% to 5%
d) none of the above
3) In a 3-phase induction motor, the rotor speed is ……. The synchronous speed.
a) greater than
b) smaller than
c) equal to
d) none of the above
4) When the rotor of a 3-phase induction motor is blocked, the slip is ……..
a) zero
b) 0.5
c) 0.1
d) 1
5) 3-phase wound rotor motors are also called ……….motors.
a) synchronous
b) slip ring
c) series
d) commutator
6) The stator of a 3-phase induction motor produces ……… magnetic filed.
a) steady
b) rotating
c) alternating
d) none of the above
7) If a 4-pole induction motor has a synchronous speed of 1500 r.p.m., then, supply frequency is ……..
a) 50 Hz
b) 25 Hz
c) 60 Hz
d) none of the above
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8) The air-gap between stator and rotor of a 3-phase induction motor ranges from ……….
a) 2 cm to 4 cm
b) 0.4 mm to 4 mm
c) 1 cm to 2 cm
d) 4 cm to 6 cm
9) At no-load, the rotor core loss of a 3-phase induction motor is ………
a) large
b) small
c) practically zero
d) none of the above
10) In the slip of induction motor increases, then, current in the stator winding ……..
a) is increased
b) is decreased
c) remains unchanged
d) none of the above