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 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 23.06 kW. 24.11 kW. 26.21 kW. 25 kW. 23.06 kW. 24.11 kW. 26.21 kW. 25 kW. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For satisfactory parallel operation of two transformers which of the following conditions is most essential, MVA rating of all transformer inversely proportional to impedance. polarities of all transformers must be same. voltage ratio of all transformers must be same. percentage impedance of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. polarities of all transformers must be same. voltage ratio of all transformers must be same. percentage impedance of all transformers must be same. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the load current and flux of a DC motor are held constant and voltage applied across it armature is increased by 5%, the speed of the motor will Depends on other factor. Remain unchanged. Increase by 5%. Reduce by 5%. Depends on other factor. Remain unchanged. Increase by 5%. Reduce by 5%. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature mmf in a dc machine is 1. stationary with respect to field poles 2. stationary with respect to armature 3. rotating with respect to field poles 4. rotating with respect to armature From these, the correct answer is 1, 3 2, 3 2, 4 1, 4 1, 3 2, 3 2, 4 1, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a transformer operating at constant voltage if the input frequency increases, the core loss increase. None of these remains constant. decrease. increase. None of these remains constant. decrease. ANSWER DOWNLOAD EXAMIANS APP
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