Electrical Machines In Ward-Leonard method of speed control, the direction of rotation of motor is reversed usually reversing the connection of the generator armature terminal. motor armature terminal. motor field terminal. generator field terminal. generator armature terminal. motor armature terminal. motor field terminal. generator field terminal. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which DC motor will have least percentage increase of input current, for the same percentage increase in the torque Compound Wound DC Motor Separately Excited DC Motor DC Series Motor DC Shunt Motor Compound Wound DC Motor Separately Excited DC Motor DC Series Motor DC Shunt Motor 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%. 82.5% 78.5% 72.5% 67.5% 82.5% 78.5% 72.5% 67.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If starter is not used with large DC motor for starting, it will damage the armature and commutator. draw a starting current many times its rated full load current. provide execessive voltage drop in line. all of above. damage the armature and commutator. draw a starting current many times its rated full load current. provide execessive voltage drop in line. all of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The oscillation in a synchronous motor can be damped out by providing damper bars in the rotor pole faces. maintaining constant excitation. oscillation cannot be damped. running the motor on leading power factors. providing damper bars in the rotor pole faces. maintaining constant excitation. oscillation cannot be damped. running the motor on leading power factors. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A separately excited DC motor has an armature resistance of 0.5 Ohm. The supply voltage is 250V. Armature current is 20A and the speed of rotation is 1500 rpm. Find the torque developed? Zero 15.6 Nm 15.28 Nm 16.55 Nm Zero 15.6 Nm 15.28 Nm 16.55 Nm ANSWER DOWNLOAD EXAMIANS APP
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