Electrical Machines In Ward-Leonard method of speed control, the direction of rotation of motor is reversed usually reversing the connection of the motor armature terminal. generator armature terminal. motor field terminal. generator field terminal. motor armature terminal. generator armature terminal. motor field terminal. generator field terminal. 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% 67.5% 82.5% 78.5% 72.5% 67.5% 82.5% 78.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 220 V dc machine has an armature resistance of 1Ω.If the full-load current is 20 A, the differenc in the induced voltages when the machine is running as a motor and as a generator is zero 40 V 50 V 20 V zero 40 V 50 V 20 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the back emf in DC motor vanishes suddenly the motor will run at very low speed. start haunting. burn. run at very high speed. run at very low speed. start haunting. burn. run at very high speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Poles of DC machine are often laminated to reduce pulsation loss. reduce armature reaction. dissipate more heat. reduce iron weight. reduce pulsation loss. reduce armature reaction. dissipate more heat. reduce iron weight. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is/are the necessary conditions for voltage build up in self excited generator? Field winding should be properly connected to armature winding. All of these Poles should contain residual flux. Field winding resistance should be less than critical resistance. Field winding should be properly connected to armature winding. All of these Poles should contain residual flux. Field winding resistance should be less than critical resistance. ANSWER DOWNLOAD EXAMIANS APP
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