Quiz No:44 Alternator RRB , Coal India , PWD , Engineering diploma Level , PSC

1. A lower voltage alternator, for the same power rating will be—-

 
 
 
 

2. Which of the following prime-movers is the least efficient?

 
 
 
 

3. One of the super-thermal power stations is being located at—

 
 
 
 

4. The difference between the synchronous speed and the actual speed of an induction motor is known as—

 
 
 
 

5. A three phase 440 V, 50 Hz induction motor has a speed of 950 r.p.m. If the machine has 6 poles, the percentage slip would be—

 
 
 
 

6. A 3-phase 440 V, 50 Hz induction motor has slip of 3%. The frequency of rotor emf will be—

 
 
 
 

7. In an induction motor 5% change in supply voltage will cause rotor torque variation of above—

 
 
 
 

8. In a induction motor if P is the power delivered to a rotor and S is the slip, then the power lost in rotor as copper loss will be—

 
 
 
 

9. Copper loss in rotor of a induction motor—

 
 
 
 

10. The rotor emf of a 3 phase, 6 pole, 400 V, 50 Hz induction motor alternate at 3 Hz. The speed of the motor will be—

 
 
 
 

11. Slip rings for induction motors are made of—

 
 
 
 

12. Starting torque of an induction motor is proportional to—

 
 
 
 

13. The data required for drawing complete circle diagram of induction motor is —

 
 
 
 

14. A 3-phase slip ring induction motor has—

 
 
 
 

15. The slip in actual induction motor is generally-

 
 
 
 

16. The maximum speed of an induction motor can not be—

 
 
 
 

17. In a squirrel cage induction motor, the starting current is—

 
 
 
 

18. When N 1 is the synchronous speed and N 2 is the actual speed of rotor, the slip is given by-

 
 
 
 

19. When f is the supply frequency and ‘S’ is the slip the frequency of rotor current is given by When a motor is switched on the rotor frequency is —

 
 
 
 

20. when a motir is switched on the rotor frequnecy is

 
 
 
 

21. In an induction motor, the rotor reactance per phase is proportional to—

 
 
 
 

22. A 7- HP, 3-phase, 400 V induction motor will draw a full load current of—

 
 
 
 

23. An induction motor is—

 
 
 
 

24. The Injected emf in the rotor of induction motor must have—

 
 
 
 

25. The running speed of a three phase induction motor is—

 
 
 
 

26. Commonly used AC motor for industrial applications is—