Electrical Machines The armature of a DC motor is laminated to reduce copper loss. friction and windage loss. eddy current loss. hysteresis loss. copper loss. friction and windage loss. eddy current loss. hysteresis loss. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The introduction of interpoles in between the main poles improves the performance of a dc machine, because the flux waveform is improved with reduction in harmonics the interpoles produce additional flux to augment the developed torque the inequality of air-gap flux on the top and bottom halves of the armature is removed a counter-emf is induced in the coil undergoing commutation the flux waveform is improved with reduction in harmonics the interpoles produce additional flux to augment the developed torque the inequality of air-gap flux on the top and bottom halves of the armature is removed a counter-emf is induced in the coil undergoing commutation ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A transformer has hysteresis loss of 30 W, at 240 V, 60 Hz. The hysteresis loss at 200 V, 50 Hz will be 36 W. 28 W. 25 W. 30 W. 36 W. 28 W. 25 W. 30 W. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous machine, if φ is the flux per pole and f is the frequency of the emf induced E then E ∝ φf E ∝ φ/f E ∝ f/φ E ∝ 1/(φf) E ∝ φf E ∝ φ/f E ∝ f/φ E ∝ 1/(φf) ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Hopkinss test in DC motor is conducted at ? Low load. No load. None of these. Full load. Low load. No load. None of these. Full load. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines DC motors are stopped by opening line switches and not by forcing the handle of the motor starter back to OFF position. This is due to occurance of Heavy sparking at the first stud of starting resistance steps. Heavy sparking at brushes. None of these. Both of above. Heavy sparking at the first stud of starting resistance steps. Heavy sparking at brushes. None of these. Both of above. ANSWER DOWNLOAD EXAMIANS APP
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