Electrical Machines The speed of a cumulatively compound DC motor can be controlled by varying Armature voltage control. Armature resistance control. Shunt field resistance control. Any of above. Armature voltage control. Armature resistance control. Shunt field resistance control. Any of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two mechanically coupled alternators deliver power at 50 Hz and 60 Hz respectively. Highest speed of alternator is 3600 rpm. 600 rpm. 3000 rpm. 500 rpm. 3600 rpm. 600 rpm. 3000 rpm. 500 rpm. 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 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 1, 2, and 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case the conditions for maximum power for DC motor are established, the efficiency of the motor will be Less than 50 % Around 90 % Any where between 75 % and 90 %. Around 100 %. Less than 50 % Around 90 % Any where between 75 % and 90 %. Around 100 %. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To increase starting torque of a 3-phase slip ring induction motor, preferred method is to increase supply frequency rotor resistance None of these supply voltage supply frequency rotor resistance None of these supply voltage ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature resistance of the dc motor is generally of the range 100 ohm. 0.1 ohm. 50 ohm. 0.5 ohm. 100 ohm. 0.1 ohm. 50 ohm. 0.5 ohm. ANSWER DOWNLOAD EXAMIANS APP
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