Electrical Machines The current drawn by a 220 V DC series motor of armature resistance 0.5 Ω and back emf of 200 V is 440 A. 400 A. 44 A. 40 A. 440 A. 400 A. 44 A. 40 A. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To eliminate the 5th harmonic in the induced voltages their respective pitch factor angle should be 36° 72° 30° 18° 36° 72° 30° 18° ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following load normally needs starting torque more than rated torque? Air compressors. Conveyers. Centrifugal pumps. Blowers. Air compressors. Conveyers. Centrifugal pumps. Blowers. 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%. 67.5% 78.5% 72.5% 82.5% 67.5% 78.5% 72.5% 82.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of a dc motor the ratio Eb / E is indicative of ratio of starting to running torque. ratio of input to output voltage. ratio of starting to running current. efficiency. ratio of starting to running torque. ratio of input to output voltage. ratio of starting to running current. efficiency. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the excitation is critical, the power factor of the alternator is None of these unity power factor. lagging power factor. leading power factor. None of these unity power factor. lagging power factor. leading power factor. ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS