Electrical Machines In a dc machine 72 number of coils are used. Find the number of commutator segments required? 72 37 74 36 72 37 74 36 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Mechanical energy is supplied to DC generator at the rate of 4200 J / s. The generator delivers 32.2 Amp at 120 V. What is the percentage efficiency of the generator? 212 V. 205 V. 201.02 V. 210 V. 212 V. 205 V. 201.02 V. 210 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is/are the necessary conditions for voltage build up in self excited generator? All of these Field winding should be properly connected to armature winding. Poles should contain residual flux. Field winding resistance should be less than critical resistance. All of these Field winding should be properly connected to armature winding. Poles should contain residual flux. Field winding resistance should be less than critical resistance. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements : For a level compounded dc generator to run at constant voltage, the series field mmf must effectively compensate 1. armature reaction mmf 2.armature resistance drop 3. brush contact voltage drop Which of these statements is/are correct ? 1, 2 and 3 1 and 3 1 and 2 2 alone 1, 2 and 3 1 and 3 1 and 2 2 alone ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of 3 - Φ IM, plugging means pulling the motor directly on line without a rotor. interchanging two supply phases for quick stopping. starting the motor on load which is more than the rated load. locking of rotor due to harmonics. pulling the motor directly on line without a rotor. interchanging two supply phases for quick stopping. starting the motor on load which is more than the rated load. locking of rotor due to harmonics. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines During hunting of a synchronous motor harmonic are developed in the armature circuit. negative phase sequence currents are generated. field excitation increases. damper bar develops torque. harmonic are developed in the armature circuit. negative phase sequence currents are generated. field excitation increases. damper bar develops torque. ANSWER DOWNLOAD EXAMIANS APP
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