Saturday, July 14, 2018

Electrical Interview questions

1. The two windings of a transformer are
 (A) conductively linked.     
 (B) inductively linked.
 (C) not linked at all.
 (D) electrically linked.

2. The power factor of a squirrel cage induction motor is
  (A) low at light load only.
  (B) low at heavy load only.
  (C) low at light and heavy load both.
  (D) low at rated load only.

3. The size of a conductor used in power cables depends on the
(A) operating voltage.         
(B) power factor.
(C) current to be carried.      
(D) type of insulation used.

4. The drive motor used in a mixer-grinder is a
(A) dc motor.
(B) induction motor.
(C) synchronous motor.           
(D) universal motor.

5. A battery
(A) always delivers power
(B) always absorbs power
(C) absorbs power when the internal resistance is non-zero but delivers power when the internal resistance is zero
(D) can absorb or deliver power depending upon the circuit to which it is connected

6.  If field current is decreased in shunt dc motor, the speed of the motor
(A) Remains Same
(B) Increases
(c) Decreases
(d) None of above

7. What is Value of resistance of individual earthing pit to be maintained?
(A) >0 <5 Ohm
(B) >5 <10 Ohm
(C) <1 Ohm
(D) >10 Ohm
8. In DC generators brushes are used for
(A) collecting of current without any sparkings
(B) collecting of voltage
(C) reduce eddy current loss
(D) convert ac armature current in to dc
9. Which of the following windings are necessary in case of all dc machines?
(A) lap winding
(B) wave winding
(C) closed winding
(D) open type winding
10. What type of Transformer used at Distribution end?
(A) Star- Delta
(B) Delta- Delta
(C) Star- Star
(D) Delta- Star

11. A circuit breaker is
(A) power factor correcting device
(B) a device to neutralize the effect of transients
(C) a waveform correcting device
(D) a current interrupting device.

12. The fault clearing time of a circuit breaker is usually
(A) few minutes
(B) few seconds
(C) one second
(D) few cycles of supply voltage.

13.  In a vacuum circuit breaker, the vacuum is of the order of
(A) 10mm Hg
(C) l0-6 mmHg
.14. No Load test on Transformer is carried out to determine
(A)  Copper loss
(B)  Magnetising current
(C) Magnetising current and loss
(D) Efficiency of Transformer
15. Dielectric Strength of Transformer is expected to be?
(A) 100 KV
(B) 330 KV
(C) 33 KV
(D) 1 KV
16. The frame of an induction motor is usually made of
(A)    Silicon steel
(B)  Cast iron
(C)  Aluminum
(D) Bronze

17. Which of the following component is usually fabricated out of silicon steel?
(A) Stator Core
(B) Bearings
(C) Shaft
(D) None of Above
18. The efficiency of an induction motor is about
(A) 100%
(B) 80-90%
(C) 50-60%
(D) less than 50%

19. Which of the following is not use as earth continuity conductor ?
(A) water pipes
(B) gas pipes
(C) structural steel members
(D)all of the above.

20. The diameter of a 50 SWG wire is closer to
(A) 0.0253 mm
(B) 0.05 mm
(C) 0.1 mm
(D) 0.5 mm.

1.      B
2.      A
3.      C
4.      D
5.      D
6.      B
7.      A
8.      A
9.      C
10.  D
11.  D
12.  D
13.  D
14.  C
15.  B
16.  B
17.  A
18.  B
19.  D
20.  A