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 28 W. 30 W. 36 W. 25 W. 28 W. 30 W. 36 W. 25 W. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider a separately excited DC motor. If the field current is increased while the armature terminal voltage is held constant, then speed of the motor will none of these. remains same. increase. Decrease.d none of these. remains same. increase. Decrease.d ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To achieve spark less commutation brushes of DC generator are rocked ahead so as to bring them in magnetic neutral axis. None of these just ahead of magnetic neutral axis. just behind the magnetic neutral axis. in magnetic neutral axis. None of these just ahead of magnetic neutral axis. just behind the magnetic neutral axis. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For the speed control of polyphase squirrel cage induction motor, if frequency of operation is decreased with constant supply voltage V, starting torque Tst decreases either of these None of these constant V, Tst increases constant supply voltage V, starting torque Tst decreases either of these None of these constant V, Tst increases ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The speed of a 50 Hz three phase induction motor under full load condition is 725 rpm the number of poles of the motor are ______________. 6. 4. 8. 2. 6. 4. 8. 2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, 1. reactance voltage is proportional to armature current 2.reactance voltage is proportional to core length 3.reactance voltage is due to self-flux of the coil undergoing commutation 4. armature-cross flux is neutralized by interpolar flux 5. interpolarmmf is more than armature mmf in the interpolar zone From these, the correct answer is 2, 3, 4 1, 3, 5 1, 2, 3, 4 1, 2, 5 2, 3, 4 1, 3, 5 1, 2, 3, 4 1, 2, 5 ANSWER DOWNLOAD EXAMIANS APP
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