Electrical Machines What is the mechanical power developed by a DC series motor is maximum? Back emf is equal to half the applied voltage. Back emf is equal to zero. None of above. Back emf is equal to applied voltage. Back emf is equal to half the applied voltage. Back emf is equal to zero. None of above. Back emf is equal to applied voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an additional resistance is connected in series with a DC series motor operating at rated speed, the speed of the motor will Remain unaltered. Increase. Oscillate around the normal speed. Reduce. Remain unaltered. Increase. Oscillate around the normal speed. Reduce. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To have sparkless commutation, the armature reaction effect in a DC machine is neutralized by increasing field excitation. compensating winding and commutating poles. shifting the brush axis from GNA to MNA. fixing the brush axis inline with the pole axis. increasing field excitation. compensating winding and commutating poles. shifting the brush axis from GNA to MNA. fixing the brush axis inline with the pole axis. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When a synchronous motor is running at synchronous speed, the damper winding produces no torque. both 1 and 2. eddy current torque. damping torqe. no torque. both 1 and 2. eddy current torque. damping torqe. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Cogging and crawling are phenomena associated with the former at a fraction of its rate speed and the latter during starting. cage induction machines and they are essentially the same. the former during starting and the latter at a fraction of its rated speed. any of the above. the former at a fraction of its rate speed and the latter during starting. cage induction machines and they are essentially the same. the former during starting and the latter at a fraction of its rated speed. any of the above. 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