Electrical Machines The material used for commutator brushes is mostly cast iron. copper. mica. carbon. cast iron. copper. mica. carbon. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-φ alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed, a field current of If1 is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current Cannot be predicted due to insufficient data. Would be equal to If1/2. Would be equal to If1. Woud be equal to 2If1. Cannot be predicted due to insufficient data. Would be equal to If1/2. Would be equal to If1. Woud be equal to 2If1. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An induction motor having 8 poles runs at 727.5 rpm. If the supply frequency is 50Hz, the emf in the rotor will have a frequency of 51.5Hz 48.5Hz 2.5Hz 1.5Hz 51.5Hz 48.5Hz 2.5Hz 1.5Hz ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of a dc motor the ratio Eb / E is indicative of ratio of starting to running torque. efficiency. ratio of input to output voltage. ratio of starting to running current. ratio of starting to running torque. efficiency. ratio of input to output voltage. ratio of starting to running current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two generators operating in parallel with rating 50MW and 100MW respectively. Both their respective governor settings are identical as 4%, consider same no load frequency. How will the machine share a common load of 100 MW 50 MW and 50 MW respectively 66.67 MW and 33.33 MW respectively any of the above 33.33 MW and 66.67 MW respectively 50 MW and 50 MW respectively 66.67 MW and 33.33 MW respectively any of the above 33.33 MW and 66.67 MW respectively ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The no load current in a transformer lags the applied voltage by about 75°. 0°. about 115°. 90°. about 75°. 0°. about 115°. 90°. ANSWER DOWNLOAD EXAMIANS APP
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