In V/f speed control of 3-phase induction motor, with increase in frequency, the slip at which maximum torque occurs None of these increase. decrease. either of these. TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following is/are the advantages of carbon brush over the copper brush? They are self lubricating in nature In case of any sparking they will be less damaged than copper brushes They are not hard as copper brush All of these TRUE ANSWER : ? YOUR ANSWER : ?
Reversing the direction of rotation of split phase motors is done by interchanging the capacitor from starting winding to main winding or vice versa. All of these reversing the terminals of main winding. reversing the terminals of starting winding. TRUE ANSWER : ? YOUR ANSWER : ?
In a dc machine 4 pole lap winding is used. The number of parallel paths are? 8 4 1 2 TRUE ANSWER : ? YOUR ANSWER : ?
The maximum possible speed at which an alternator can be driven to generate 50 Hz and 4000 V is 3000 rpm. 4000 rpm. 3600 rpm. 1500 rpm. TRUE ANSWER : ? YOUR ANSWER : ?
In which of the following generators negative voltage regulation can occur? over compound generator series generators shunt generator both B and C TRUE ANSWER : ? YOUR ANSWER : ?
Two generators G1 and G2 are to be operated in parallel to deliver a total current of 60 A. Generator one has a terminal voltage of 280 V on no load and 240 V when supplying 40 A current. Similarly the second generator has a voltage of 300 V when on no load and 240 V when supplying of 50 A of current. The output voltage of each generator will be 256.4 V. 238.2 V. 271.7 V. 240 V. TRUE ANSWER : ? YOUR ANSWER : ?
Transformer core is laminated to reduce both 1 and 2. hysteresis loss. eddy current loss. copper loss. TRUE ANSWER : ? YOUR ANSWER : ?
Two identical loss less series motors connected in series across a dc supply voltage, runs at speed of N1 and N2, then ratio of their output power is N12 : N22. N1 : N2. none. 1 : 1. TRUE ANSWER : ? YOUR ANSWER : ?
What will be the e.m.f. generated by a 4 pole lap connected DC Generator rotating at 1500 r.p.m.? Its flux per pole is 0.4 mWb and total no of armature conductors is 1000. 30 volts. 40 volts. 10 volts. 20 volts. TRUE ANSWER : ? YOUR ANSWER : ?