Electrical Machines A 4-pole dc generator runs at 1500 rpm. The frequencyof current in the armature winding is 100 Hz 0 Hz 50 Hz 25 Hz 100 Hz 0 Hz 50 Hz 25 Hz ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What happens if fifth multiples of harmonics is given to induction motor? It will rotates in normal operation. Fail to start. It will rotates in reverse direction. Either short circuit or open circuit occurs. It will rotates in normal operation. Fail to start. It will rotates in reverse direction. Either short circuit or open circuit occurs. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of following methods are suitable for the speed control of squirrel cage induction motor? 1. Voltage control. 2. Frequency control. 3. Pole changing method. 4. Rotor resistance control select the correct answer using the codes given below:- 2, 3 and 4. 1, 2 and 3. 2 and 4. 1, 3 and 4. 2, 3 and 4. 1, 2 and 3. 2 and 4. 1, 3 and 4. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, 1. reactance voltage is proportional to armature current 2.reactance voltage is proportional to core length 3.reactance voltage is due to self-flux of the coil undergoing commutation 4. armature-cross flux is neutralized by interpolar flux 5. interpolarmmf is more than armature mmf in the interpolar zone From these, the correct answer is 1, 3, 5 1, 2, 3, 4 2, 3, 4 1, 2, 5 1, 3, 5 1, 2, 3, 4 2, 3, 4 1, 2, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Compensating windings are used in DC generators to neutralize the cross magnetizing effect of the armature reaction. mainly to reduce the eddy currents by providing local short circuit. to provide path for the circulation of cooling air. None of these to neutralize the cross magnetizing effect of the armature reaction. mainly to reduce the eddy currents by providing local short circuit. to provide path for the circulation of cooling air. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In an alternator the voltage generated per phase is proportional to number of turns in coil. flux per pole. frequency of waveform. All of these number of turns in coil. flux per pole. frequency of waveform. All of these ANSWER DOWNLOAD EXAMIANS APP