Electrical Machines The frequency of voltage generated by an alternator having 8 poles and rotating at 250 rpm is 60 Hz. 16.67 Hz. 25 Hz. 50 Hz. 60 Hz. 16.67 Hz. 25 Hz. 50 Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the speed of stator rotating magnetic field with respect to rotor rotating magnetic field? Slip speed Synchronous speed Zero None of these Slip speed Synchronous speed Zero None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Fufuraldehyde analysis is done to determine the condition of cork gaskets used in transformer. condition of paper insulation in transformer. condition of lamination on CRGO steel sheet. condition of oil in transformer. condition of cork gaskets used in transformer. condition of paper insulation in transformer. condition of lamination on CRGO steel sheet. condition of oil in transformer. 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 3 1, 2 and 4 2, 3 and 4 1 and 3 1, 2, and 3 1, 2 and 4 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What happens if fifth multiples of harmonics is given to induction motor? It will rotates in reverse direction. Fail to start. It will rotates in normal operation. Either short circuit or open circuit occurs. It will rotates in reverse direction. Fail to start. It will rotates in normal operation. Either short circuit or open circuit occurs. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines It is an advisable to use auto transformer if the transformation ratio is Greater than 1. 0.25. 0.5. near to 1. Greater than 1. 0.25. 0.5. near to 1. ANSWER DOWNLOAD EXAMIANS APP
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