Electrical Machines The current drawn by the a 230 V DC motor of armature resistance 0.5 Ω and back emf 200 V is 40 660 60 600 40 660 60 600 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In induction motor when the length of the air gap is increased, the magnetizing current of the motor increases while the short circuit current __________________. remains unchanged. kept constant to certain value. increased. decreased. remains unchanged. kept constant to certain value. increased. decreased. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A self-excited shunt generator fails to build up, because 1. the field circuit is open 2. The armature circuit is open 3. the residual magnetism is absent 4. The direction of rotation is wrong From these, the correct answer is 1, 3 3 only 1, 2 and 3 1, 2, 3 and 4 1, 3 3 only 1, 2 and 3 1, 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 400 V, 50 Hz, 30 Hp, three phase IM is drawing 50 A current at 0.8 p.f lagging. The stator and rotor copper losses are 1.5 KW and 900 W respectively. The friction and windage losses are 1050 W and core losses are 1200 W. The air gap power of the motor will be 24.11 kW. 26.21 kW. 25 kW. 23.06 kW. 24.11 kW. 26.21 kW. 25 kW. 23.06 kW. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The principle of operation of a 3 - Φ induction motor is almost similar to that of repulsion start induction motor. capacitor start induction motor. transformer with secondary short circuited. synchronous motor. repulsion start induction motor. capacitor start induction motor. transformer with secondary short circuited. synchronous motor. 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. percentage impedance of all transformers must be same. voltage ratio of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. polarities of all transformers must be same. percentage impedance of all transformers must be same. voltage ratio of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. ANSWER DOWNLOAD EXAMIANS APP
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