A. high inductance arid low resistance
B. low inductance and high resistance
C. low inductance and low resistance
D. high inductance and high resistance
✅ The correct answer is option A.
Polyphase Induction Motors MCQs
2. The low power factor of induction motor is due to___________?
A. rotor leakage reactance
B. stator reactance
C. the reactive lagging magnetizing current necessary to generate the magnetic flux
D. all of the above
✅ The correct answer is option D.
3. Temperature of the stator winding of a three phase induction motor is obtained by___________?
A. resistance rise method
B. thermometer method
C. embedded temperature method
D. all above methods
✅ The correct answer is option D.
4. Insertion of resistance in the rotor of an induction motor to develop a given torque?
A. decreases the rotor current
B. increases the rotor current
C. rotor current becomes zero
D. rotor current rernains same
✅ The correct answer is option D.
5. In induction motor, percentage slip depends on__________?
A. supply frequency
B. supply voltage
C. copper losses in motor
D. none of the above
✅ The correct answer is option C.
6. In an induction motor if air-gap is increased__________?
A. the power factor will be low
B. windage losses will be more
C. bearing friction will reduce
D. copper loss will reduce In an induction motor
✅ The correct answer is option A.
7. When /?2 is the rotor resistance, .X2 the rotor reactance at supply frequency and s the slip, then the condition for maximum torque under running conditions will be_____________?
A. sR2X2 = 1
B. sR2 = X2
C. R2 = sX2
D. R2 = s2X2
✅ The correct answer is option C.
8. The frame of an induction motor is usually made of____________?
A. silicon steel
B. cast iron
C. aluminium
D. bronze
✅ The correct answer is option B.
9. Insertion of reactance in the rotor circuit_______?
A. reduces starting torque as well as maximum torque
B. increases starting torque as well as maximum torque
C. increases starting torque but maxi-mum torque remains unchanged
D. increases starting torque but maxi-mum torque decreases
✅ The correct answer is option A.
10. For driving high inertia loads best type of induction motor suggested is_____________?
A. slip ring type
B. squirrel cage type
C. any of the above
D. none of the above
✅ The correct answer is option A.