Related Questions

When the equivalent circuit diagram of doouble squirrelcage induction motor is constructed the two cages can be considered
A in series
B in parallel
C in series-parallel
D in parallel with stator
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
In medium sized induction motors, the slip is generally around
A 0.04 %
B 0.4 %
C 4 %
D 14 %
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 induction motors, the length of air gap in kept as small as mechanically possible is order to have
A low power factor
B high power factor
C high over load capacity
D any of the above
For three-phase induction motors which of the following is the least efficient method of speed control?
A Cascade control
B Pole changing
C Rheostat control
D Combination of cascade and pole changing
In three-phase induction motors sometimes copper bars are placed deep in the rotor to
A Improve starting torque
B Reduce copper losses
C Improve efficiency
D Improve power factor
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
In case of the induction motors the torque is
A Inversely proportional to $$\left( {\sqrt {{\text{slip}}} } \right)$$
B Directly proportional to $${\left( {{\text{slip}}} \right)^2}$$
C Inversely proportional to slip
D Directly proportional to slip
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

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