Electrical Machines If s is the slip and f is the supply frequency of an induction motor, the frequency of rotor current is given by sf. f / s. sf / 2. s2. sf. f / s. sf / 2. s2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a loaded DC motor, if the brushes are given a shift from the interpolar axis in the direction of rotation, then the commutation will improve and the speed rises. improve and the speed falls. deteriorate and the speed falls. deteriorate and the speed rises. improve and the speed rises. improve and the speed falls. deteriorate and the speed falls. deteriorate and the speed rises. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a single phase transformer the magnitude of leakage reactance is twice that of resistance of both primary and secondary. With secondary short circuited, the input power factor is 1/3 1/√2 2/√5 1/√5 1/3 1/√2 2/√5 1/√5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines During hunting of a synchronous motor field excitation increases. negative phase sequence currents are generated. damper bar develops torque. harmonic are developed in the armature circuit. field excitation increases. negative phase sequence currents are generated. damper bar develops torque. harmonic are developed in the armature circuit. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following is/are the advantages of carbon brush over the copper brush? All of these They are self lubricating in nature They are not hard as copper brush In case of any sparking they will be less damaged than copper brushes All of these They are self lubricating in nature They are not hard as copper brush In case of any sparking they will be less damaged than copper brushes ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor is running at rated speed without any additional resistance in series. If an additional resistance is placedin series, the speed of motor Oscillates around the rated speed. Increases. Decreases. Remains unchanged. Oscillates around the rated speed. Increases. Decreases. Remains unchanged. ANSWER DOWNLOAD EXAMIANS APP
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