In circle diagram for induction motor, diameter of circle represents which of the following ? Slip. Running torque. Line voltage. Rotor current. TRUE ANSWER : ? YOUR ANSWER : ?
Torque developed in the rotor is not dependent on the slip inversely proportional to slip either of these directly proportional to slip TRUE ANSWER : ? YOUR ANSWER : ?
What are the starters used for starting of cage motors? Auto transformer starter. DOL starter. Star-delta starter. All of these. TRUE ANSWER : ? YOUR ANSWER : ?
What is the necessity of copper brushes in a dc motors? To convert alternating supply current to direct current. None of these. To absorb the mechanical shocks produced during running condition. To increase the flux cutting by the rotor. TRUE ANSWER : ? YOUR ANSWER : ?
The armature reaction mmf in a DC machines has a form of trapezoidal. rectangular. triangular. sinusoidal. TRUE ANSWER : ? YOUR ANSWER : ?
In DC machines, the interpoles are provided to counteract demagnetizing effect of armature mmf in commutating zone. to make commutation spark less. both (B) and (C). to counteract the reactance voltage and the cross-magnetizi TRUE ANSWER : ? YOUR ANSWER : ?
In a single phase transformer the magnitude of leakage reactance is twice that of resistance of both primary and secondary. With secondary short circuited, the input power factor is 1/√2 1/√5 1/3 2/√5 TRUE ANSWER : ? YOUR ANSWER : ?
To control the speed of an induction motor, the supply frequency is reduced by 10%. For the same magnetizing current to remain constant, the supply voltage must be reduced by 20% increased by 10% reduced by 10% increased by 20% TRUE ANSWER : ? YOUR ANSWER : ?
In DC generators brushes are used for convert ac armature current in to dc reduce eddy current loss collecting of current without any sparkings collecting of voltage TRUE ANSWER : ? YOUR ANSWER : ?
R1 is the resistance of the primary winding of the transformer. The turn ratio in terms of primary to secondary is K. Then the equivalent resistance of the primary referred to secondary is K×R1 R1 /K K²R1 R1 /K² TRUE ANSWER : ? YOUR ANSWER : ?