Electrical Machines The supply voltage to an induction motor is reduced by 10%. By what percentage, approximately, will the maximum torque decrease? 10% 19% 40% 5% 10% 19% 40% 5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Transformer cooling and insulating oil must be of low resistivity. low viscosity. low BDV. high viscosity. low resistivity. low viscosity. low BDV. high viscosity. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The function of field regulator in a DC compound motor is to control field current. none of above. vary the armature resistance. limit the armature current. control field current. none of above. vary the armature resistance. limit the armature current. 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%. 82.5% 72.5% 67.5% 78.5% 82.5% 72.5% 67.5% 78.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the back emf in DC motor vanishes suddenly the motor will burn. run at very high speed. start haunting. run at very low speed. burn. run at very high speed. start haunting. run at very low speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Ratio of starting torque to full load torque is minimum in Series motor. Cumulative compound motor. Shunt motor. Differential compound motor. Series motor. Cumulative compound motor. Shunt motor. Differential compound motor. ANSWER DOWNLOAD EXAMIANS APP
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