Search
.Management Sciences
Category: Polyphase Induction Motors
Which is of the following data is required to draw the circle diagram for an induction motor ?
A. Block rotor test only
B. No load test only
C. Block rotor test and no-load test
D. Block rotor test, no-load test and stator resistance test
In case of the induction motors the torque is___________?
A. inversely proportional to (Vslip)
B. directly proportional to (slip)2
C. inversely proportional to slip
D. directly proportional to slip
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
Short-circuit test on an induction motor cannot be used to determine___________?
A. windage losses
B. copper losses
C. transformation ratio
D. power scale of circle diagram
The number of slip rings on a squirrel cage induction motor is usually____________?
A. two
B. three
C. four
D. none
The ‘crawling” in an induction motor is caused by___________?
A. high loads
B. low voltage supply
C. improper design of machine
D. harmonics developed in the motor
In an induction motor the relationship between stator slots and rotor slots is that_____________?
A. stator slots are equal to rotor slots
B. stator slots are exact multiple of rotor slots
C. stator slots are not exact multiple of rotor slots
D. none of the above
The crawling in the induction motor is caused by____________?
A. low voltage supply
B. high loads
C. harmonics develped in the motor
D. improper design of the machine
E. none of the above
A pump induction motor is switched on to a supply 30% lower than its rated voltage. The pump runs. What will eventually happen ? It will____________?
A. stall after sometime
B. stall immediately
C. continue to run at lower speed without damage
D. get heated and subsequently get damaged
Recent Comments