Electrical Machines If the back emf in DC motor vanishes suddenly the motor will run at very high speed. burn. run at very low speed. start haunting. run at very high speed. burn. run at very low speed. start haunting. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If direct axis reactance Xd and quadrature axis reactance Xq are equal, then reluctance power is zero maximum All of these minimum zero maximum All of these minimum 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. fixing the brush axis inline with the pole axis. shifting the brush axis from GNA to MNA. increasing field excitation. compensating winding and commutating poles. fixing the brush axis inline with the pole axis. shifting the brush axis from GNA to MNA. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For satisfactory parallel operation of two transformers which of the following conditions is most essential, polarities of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. percentage impedance of all transformers must be same. voltage ratio of all transformers must be same. polarities of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. percentage impedance of all transformers must be same. voltage ratio of all transformers must be same. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For the speed control of polyphase squirrel cage induction motor, if frequency of operation is decreased with None of these either of these constant supply voltage V, starting torque Tst decreases constant V, Tst increases None of these either of these constant supply voltage V, starting torque Tst decreases constant V, Tst increases ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Equalizer rings are used in which of the followings? wave winding both 1 and 2 None of these lap winding wave winding both 1 and 2 None of these lap winding ANSWER DOWNLOAD EXAMIANS APP