Related Questions

Blocked rotor test on induction motors is used to find out
A Leakage reactance
B Power factor on short circuit
C Short-circuit current under rated voltage
D All of the above
In squirrel cage induction motors, the rotor slots are usually given slight skew in order to
A Reduce windage losses
B Reduce eddy currents
C Reduce accumulation of dirt and dust
D Reduce magnetic hum
Which type of bearing is provided in small induction motors to support the rotor shaft?
A Ball bearings
B Cast iron bearings
C Bush bearings
D None of the above
A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is
A Slop speed operation
B High starting torque
C Low windage losses
D All of the above
The power input to an induction motor is 50 kW when it is running at 4% slip. If the stator resistance and core losses are neglected, the rotor copper loss is
A 30 kW
B 20 kW
C 2 kW
D 4 kW
If 2 kg of metal, of which 1/3 is zine and the rest is copper , be mixed with 3 kg of metal, of which 1/4 is zinc and the rest is copper , then what will be the ratio of zinc to copper in the mixture?
A 17 : 43
B 13 : 42
C 19 : 43
D 15 : 42
If 2 kg of metal, of which 1/3 is zinc and the rest is copper s, be mixed with 3 kg of metal , of which 1/4 is zinc and the rest is copper , then what will be the ratio of zinc to copper in the mixture?
A 13 : 42
B 19 : 43
C 15 : 42
D 17 : 43
In working stress design, permissible bond stress in the case of deformed bars is more than that in plain bars by
A 10%
B 20%
C 30%
D 40%
Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors?
A Low cost
B Wide speed range
C Stability
D High starting torque
When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop
A inductor motor torque
B induction generator torque
C synchronous motor torque
D d.c. motor toque

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