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 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 the flux waveform is improved with reduction in harmonics the interpoles produce additional flux to augment the developed torque ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 78.5% 67.5% 82.5% 72.5% 78.5% 67.5% 82.5% 72.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the temperature of armature resistance is increased, the speed of a series motor would not change. decrease. None of above. increase. not change. decrease. None of above. increase. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines How can the synchronous speed of a 3 - Φ IM be varied? By varying number of poles. By varying the supply frequency. Both (A) and (B). By varying supply voltage. By varying number of poles. By varying the supply frequency. Both (A) and (B). By varying supply voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 250 volt dc series motor having an armature resistance of 0.2 Ω takes a load current of 60 A. What will be the torque produced at the shaft of the motor? Consider brush drop of 1V. can not be determined. 133.22 N-m 266.20 N-m. 234.76 N-m. can not be determined. 133.22 N-m 266.20 N-m. 234.76 N-m. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3 - φ induction motor can also be referred to as a transformer. repulsion motor. shunt motor. asynchronous motor. transformer. repulsion motor. shunt motor. asynchronous motor. ANSWER DOWNLOAD EXAMIANS APP
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