Electrical Machines The introduction of interpoles in between the main poles improves the performance of a dc machine, because the inequality of air-gap flux on the top and bottom halves of the armature is removed the interpoles produce additional flux to augment the developed torque a counter-emf is induced in the coil undergoing commutation the flux waveform is improved with reduction in harmonics the inequality of air-gap flux on the top and bottom halves of the armature is removed the interpoles produce additional flux to augment the developed torque a counter-emf is induced in the coil undergoing commutation the flux waveform is improved with reduction in harmonics ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The shaft torque of a dc motor is less than the electromagnetic torque because of mechanical losses. eddy current losses. ohmic losses. hysteresis losses. mechanical losses. eddy current losses. ohmic losses. hysteresis losses. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In large sized DC machines the compensating windings are provided to neutralize voltage induced in coil due to fluctuation of l reduce eddy current losses by providing local short circuits. None of these compensate for the decrease in speed due to increase of load. neutralize voltage induced in coil due to fluctuation of l reduce eddy current losses by providing local short circuits. None of these compensate for the decrease in speed due to increase of load. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 230 V, 50 Hz, 4 pole single phase induction motor is rotating in the clockwise ( forward ) direction at a speed of 1425 rpm. If the rotor resistance at standstill is 7.8 Ω. Then the effective rotor resistance in the backward branch of the equivalent circuit will be 4 Ω. 10 Ω. 8 Ω. 2 Ω. 4 Ω. 10 Ω. 8 Ω. 2 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3 - Φ, 12 pole, 600 V, 50 Hz star connected IM has rotor resistance and stand still resistance of 0.03 Ω and 0.5 Ω respectively. The speed of maximum torque will be 470 rpm. 540 rpm. 450 rpm. 240 rpm. 470 rpm. 540 rpm. 450 rpm. 240 rpm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3- phase synchronous motor can operate over a wide range of power factors i.e. from lagging to leading power factor. This is achieved by varying the applied voltage. changing the field excitation. varying the speed. changing the load. varying the applied voltage. changing the field excitation. varying the speed. changing the load. ANSWER DOWNLOAD EXAMIANS APP
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