Electrical Machines Which of the following methods of speed control is not affected through stator side? Change of rotor resistance. Change of number of pole. Change of supply voltage. Change of supply frequency. Change of rotor resistance. Change of number of pole. Change of supply voltage. Change of supply frequency. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In DC generator, armature reaction refers to what? Effect of field flux on the armature flux. Effect of armature flux on the load. Effect of armature flux on the main field flux. None of these Effect of field flux on the armature flux. Effect of armature flux on the load. Effect of armature flux on the main field flux. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which type of motors are preferred in lifts? None of these DC compound motors. DC shunt motors. DC series motors. None of these DC compound motors. DC shunt motors. DC series motors. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor has which of the following characteristics? Can be started easily without load. Has a almost constant speed. Has a poor torque. Has its field winding consinting of thick wire and less no of turns. Can be started easily without load. Has a almost constant speed. Has a poor torque. Has its field winding consinting of thick wire and less no of turns. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a single phase capacitor start induction motor which of the following is valid? Rotation can be changed by reversing main winding terminals. Direction of rotation cannot be changed. None of these. Rotation can be changed by interchanging supply terminals. Rotation can be changed by reversing main winding terminals. Direction of rotation cannot be changed. None of these. Rotation can be changed by interchanging supply terminals. 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% 67.5% 72.5% 82.5% 78.5% 67.5% 72.5% ANSWER DOWNLOAD EXAMIANS APP
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