Electrical Machines Demagnetization effects which of the following? both B and C commutation reduces the terminal voltage reduction in main field flux both B and C commutation reduces the terminal voltage reduction in main field flux ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3 - Φ, 4 pole IM is supplied from a 50 Hz source. Calculate rotor frequency when rotor runs 600 rpm? 20 Hz. 30 Hz. Can be determined. 35 Hz. 20 Hz. 30 Hz. Can be determined. 35 Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 72.5% 82.5% 78.5% 67.5% 72.5% 82.5% 78.5% 67.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When the mechanical power is developed by a DC motor maximum back emf is equal to applied voltage. Back emf is equal. None of above. Back emf is equal to half of applied voltage. back emf is equal to applied voltage. Back emf is equal. None of above. Back emf is equal to half of applied voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The oscillation in a synchronous motor can be damped out by maintaining constant excitation. providing damper bars in the rotor pole faces. oscillation cannot be damped. running the motor on leading power factors. maintaining constant excitation. providing damper bars in the rotor pole faces. oscillation cannot be damped. running the motor on leading power factors. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Resistance commutation is used generally in case of None of these DC machines bellow 5 kW. DC machines above 10 kW. fractional kW DC machines. None of these DC machines bellow 5 kW. DC machines above 10 kW. fractional kW DC machines. ANSWER DOWNLOAD EXAMIANS APP
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