Temperature of the stator winding of a three phase induction motor is obtained by___________? A. resistance rise method B. thermometer method C. embedded temperature methodD. all above methods
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
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 zeroD. rotor current rernains same
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…
An induction motor can run at synchronous speed when____________? A. it is run on load B. it is run in reverse direction C. it is run on voltage higher than the rated voltageD. e.m.f. is injected in the rotor circuit
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 fluxD. all of the above
In induction motor, percentage slip depends on__________? A. supply frequency B. supply voltageC. copper losses in motor D. none of the above
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 = X2C. R2 = sX2 D.…
In case of a double cage induction motor, the inner cage has__________? A. high inductance arid low resistance B. low inductance and high resistance C. low inductance and low resistance D. high inductance and high resistance
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