Electrical Machines When the mechanical power is developed by a DC motor maximum Back emf is equal to half of applied voltage. Back emf is equal. back emf is equal to applied voltage. None of above. Back emf is equal to half of applied voltage. Back emf is equal. back emf is equal to applied voltage. None of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Slot wedges in a dc machine is made up of cast iron. mild steel. silicon steel. fibre. cast iron. mild steel. silicon steel. fibre. 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 : 2, 3 and 4 1 and 3 1, 2 and 4 1, 2, and 3 2, 3 and 4 1 and 3 1, 2 and 4 1, 2, and 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The maximum possible speed at which an alternator can be driven to generate 50 Hz and 4000 V is 1500 rpm. 3600 rpm. 3000 rpm. 4000 rpm. 1500 rpm. 3600 rpm. 3000 rpm. 4000 rpm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt generator builds up 230 V when driven in clockwise direction. In case it is driven in anti clockwise direction, other things remaining unchanged, then the voltage build up is 230 V not possible some what more than 230 V some what less than 230 V 230 V not possible some what more than 230 V some what less than 230 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Scott connections are used for single phase to three phase transformation. three phase to two phase transformation. any of the above. three phase to single phase transformation. single phase to three phase transformation. three phase to two phase transformation. any of the above. three phase to single phase transformation. ANSWER DOWNLOAD EXAMIANS APP
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