Two transformers with identical rating, are designed with flux densities of 1.2 and 1.4 Wb / m2 respectively. The weight of first transformer per kVA is more than that of second transformer. equal to that of second transformer. less than that of second transformer. none of these. TRUE ANSWER : ? YOUR ANSWER : ?
In synchronous motor the torque is proportional to Power P 1/P 1/P² P² TRUE ANSWER : ? YOUR ANSWER : ?
A DC compound motor has both shunt and series field winding. only series field winding. tertiary winding. only shunt field winding. TRUE ANSWER : ? YOUR ANSWER : ?
To get the speed of DC motor is more than normal without wastage of electrical energy _____________ is used. Ward Leonard control. None of above. Rheostatic control. Any of above method. TRUE ANSWER : ? YOUR ANSWER : ?
Transformer core is laminated to reduce copper loss. hysteresis loss. eddy current loss. both 1 and 2. TRUE ANSWER : ? YOUR ANSWER : ?
In DC machines, the interpoles are provided to counteract the reactance voltage and the cross-magnetizi both (B) and (C). to make commutation spark less. to counteract demagnetizing effect of armature mmf in commutating zone. TRUE ANSWER : ? YOUR ANSWER : ?
What is the effect of armature reaction ? Armature flux distorts the main field flux. Armature flux weakens the main field flux. None of the options. Both option B and C. TRUE ANSWER : ? YOUR ANSWER : ?
Voltage across the open circuited field termninals of a synchorous machine under slip test is DC of slip frequency. DC. AC of supply frequency. A modulated supply frequency AC voltage with slip frequency envelop. TRUE ANSWER : ? YOUR ANSWER : ?
Resistance commutation is used generally in case of None of these DC machines above 10 kW. fractional kW DC machines. DC machines bellow 5 kW. TRUE ANSWER : ? YOUR ANSWER : ?
There are two 2-pole DC machines. Main field axis of machine A is horizontal and that of B is vertical. It is preferable to purchase any of the two machines none of these machine A machine B TRUE ANSWER : ? YOUR ANSWER : ?