Electrical Machines If the back emf in DC motor vanishes suddenly the motor will run at very low speed. start haunting. run at very high speed. burn. run at very low speed. start haunting. run at very high speed. burn. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC Shunt Motor having shunt field resistance of 250 Ω and armature resistance of 0.5 Ω is connected to 250 V supply and load current of 21 A. What is the back emf generated ? 150 V. 210 V 230 V. 240 V. 150 V. 210 V 230 V. 240 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Autotransformer makes effective saving on copper and copper losses, when its transformation ratio is equal to less than one. greater than one. very low approx to one. less than one. greater than one. very low approx to one. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 2 pole synchronous machine is operating at 3000 rpm. Find the relation between electrical angular momentum (ωe) and mechanical angular momentum (ωm) ? ωe = 2*ωm ωe = 4*ωm ωe = ωm ωe = 1/2*ωm ωe = 2*ωm ωe = 4*ωm ωe = ωm ωe = 1/2*ωm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In which of the following motors DC excitation is not required? hysteresis motor 3-phase synchronous generator 3-phase synchronous motor reluctance motor hysteresis motor 3-phase synchronous generator 3-phase synchronous motor reluctance motor ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Hunting in a synchronous motor takes place when power factor is unity. when load varies. when supply voltage fluctuates. motor is under loaded. when power factor is unity. when load varies. when supply voltage fluctuates. motor is under loaded. ANSWER DOWNLOAD EXAMIANS APP
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