Electrical Machines Field divertor method of speed control of a DC series motor gives speed above rated one due to reduction of Line current. None of above. Armature current. Field current. Line current. None of above. Armature current. Field current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following factors improve commutation in a dc machine ? 1. High contact resistance of brushes 2. High inductance of the coils undergoing commutation 3. Shifting of brushes in the direction of rotation for a generator and in the opposite direction For a motor 4. Narrow width for the commutation bars Select the correct answer using the codes given below : Codes : 1, 2, and 3 1 and 3 1, 2 and 4 2, 3 and 4 1, 2, and 3 1 and 3 1, 2 and 4 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A transformer core is made up of a silicon steel laminations which has maximum flux density 1 Tesla. If it was cold rolled grain oriented its flux density increases to 1.6 Tesla. What is the saving in core size or area due to cold rolled grain oriented process? 40% 68% 38% 60% 40% 68% 38% 60% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In DC generator, armature reaction refers to what? None of these Effect of armature flux on the main field flux. Effect of field flux on the armature flux. Effect of armature flux on the load. None of these Effect of armature flux on the main field flux. Effect of field flux on the armature flux. Effect of armature flux on the load. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of a conductively compensated DC series motor, the compensating winding is provided As a separate unit. In parallel with the field winding. In parallel with the armature winding. In series with the armature winding. As a separate unit. In parallel with the field winding. In parallel with the armature winding. In series with the armature winding. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For high current and low current rating which winding is employed to DC machine? None of above Wave winding Both lap and wave winding Lap winding None of above Wave winding Both lap and wave winding Lap winding ANSWER DOWNLOAD EXAMIANS APP
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