Electrical Machines A 4 pole, 3-phase induction motor is running at 4% slip at full load. If the speed of the motor is 720 rpm, the supply frequency is 25 Hz 60 Hz 50 Hz 40 HZ 25 Hz 60 Hz 50 Hz 40 HZ ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To increase starting torque of a 3-phase slip ring induction motor, preferred method is to increase supply voltage rotor resistance None of these supply frequency supply voltage rotor resistance None of these supply frequency ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two synchronous generators operating in parallel 200 MW and 400 MW respectively. The drooping characteristics of their governors are identical as 4% from no load to full load. Consider the governors operating at 50Hz on no load. What is the operating frequency, if the load is 600 MW? 48.5 Hz 48 Hz 50 Hz 45 HZ 48.5 Hz 48 Hz 50 Hz 45 HZ ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The power factor of an induction motor operating at no load will have a value around unity 0.2 lag 0.9 lag 0.2 lead unity 0.2 lag 0.9 lag 0.2 lead 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, 2 and 4 1, 2, and 3 1 and 3 2, 3 and 4 1, 2 and 4 1, 2, and 3 1 and 3 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 some what less than 230 V some what more than 230 V 230 V not possible some what less than 230 V some what more than 230 V 230 V not possible ANSWER DOWNLOAD EXAMIANS APP
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