In a synchronous motor torque or load angle δ ------------- with increase in load remains unaffected decreases increases None of these TRUE ANSWER : ? YOUR ANSWER : ?
In a loaded DC motor, if the brushes are given a shift from the interpolar axis in the direction of rotation, then the commutation will deteriorate and the speed falls. deteriorate and the speed rises. improve and the speed falls. improve and the speed rises. TRUE ANSWER : ? YOUR ANSWER : ?
How can the synchronous speed of a 3 - Φ IM be varied? By varying number of poles. Both (A) and (B). By varying supply voltage. By varying the supply frequency. TRUE ANSWER : ? YOUR ANSWER : ?
What is power factor of a 3 - φ induction motor at no load? High. Equal to 1. Same as full load. Low. TRUE ANSWER : ? YOUR ANSWER : ?
What does the use the of height flux density value in transformer design lead to? Reduced copper loss. Increase in weight/KVA. Decrease in weight/KVA. Reduced iron loss. TRUE ANSWER : ? YOUR ANSWER : ?
The following statements relate to compensating winding (CW) and interpole winding (IW) of a dc machine : 1. CW neutralizes the armature reaction under a pole pitch 2. IW is connected in series with armature circuit 3. IW produces mmf in the commutating zone only 4. CWmmf is directed along the brush axis 5. Mmf produced by IW is equal to armature mmf From these, the correct statements are 1, 2, 3, 4 and 5 2, 3, 4 1, 3, 4, 5 2, 3, 4, 5 TRUE ANSWER : ? YOUR ANSWER : ?
Synchronous condensers are used to reduce hunting improve the power factor All of these improve starting torque TRUE ANSWER : ? YOUR ANSWER : ?
The speed of a motor falls from 1100 r.p.m at no-load to 1050 r.p.m at rated load. The speed regulation of motor is 4.76%. 3.76%. 2.56 %. 2.57 %. TRUE ANSWER : ? YOUR ANSWER : ?
A 4 pole 50 Hz 1-phase induction motor is running at 1470 rpm. Find the forward and backward slips? 0.04, 1.96 0.04, 0.96 0.02, 1.98 0.02, 0.98 TRUE ANSWER : ? YOUR ANSWER : ?
The application that need frequent starting and stopping is jaw crushers. blowers. paper mills. lifts and hoists. TRUE ANSWER : ? YOUR ANSWER : ?