Electrical Machines A 4 pole dc generator is running at 1500 rpm the frequency of current in the armature winding is 100Hz. 150Hz. 200Hz. 50Hz. 100Hz. 150Hz. 200Hz. 50Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A commutator in DC machines can 1. provide half-wave rectification 2. Provide full-wave rectification 3. convert ac to dc 4. Convert dc to ac 5. provide controlled full-wave rectification From these, the correct answer is 2, 3, 4 2, 3 ,5 1, 2, 3 2, 3, 4, 5 2, 3, 4 2, 3 ,5 1, 2, 3 2, 3, 4, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If in a sub – station there is one 132 / 33 kV transformer whose secondary is connected with primary of one 33 / 11 kV transformer, the total transformation ratio of the sub – station will be, 7. 12. 3. 4. 7. 12. 3. 4. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The use of higher flux density in the transformer design None of these reduces the weigh per KVA increases the weigh per KVA has no relation with the weight of transformer None of these reduces the weigh per KVA increases the weigh per KVA has no relation with the weight of transformer 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. Reduce. Oscillate around the normal speed. Increase. Remain unaltered. Reduce. Oscillate around the normal speed. Increase. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC machine, the angle between the stator and rotor fields is dependent upon the load. 90o. 180o. 0o. dependent upon the load. 90o. 180o. 0o. ANSWER DOWNLOAD EXAMIANS APP
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