DMRC Previous Year Papers

Hey buddy will you please get the DMRC Electrical Engineer exam paper so that I can solve it and prepare for it easily?

Don’t worry buddy I will help you here to get the DMRC Electrical Engineer exam paper so that you can have idea about the exam.

Here is the exam paper

1. A transformer transforms
a. frequency
b. voltage
c. current
d. voltage and current

2. Which of the following is the basic element of transformer
a. core
b. primaryb winding
c. secondary winding
d. mutual flux

3. In an ideal transformer
a. winding has no resistance
b. core has no losses
c. core has infinite permeanility
d. all of the above

4. The maun purpose of using core in a transformer is to
a. decrease iron losses
b. prevent eddy current losses
c.ilininate magnetic hysteresis
d. decrease reluctance of comman magnetic circuit

5. Transformer cores are laminated in order to
a. simplify its construction
b. minimise eddy current losses
c. reduce cost
d. reduce hysterisis loss

6. A transformer having 1000 primary turns is connected to a 250 volt ac
supply, for a secondary voltafge of 400 volt, the no. secondary turns should
be
a. 1600
b. 250
c. 400
d. 1250

7. The primary and secondary induced emf E1 & E2 in a 2 winding
transformer are always
a. equal in magnitude
b. antiphase with each other
c. Inphase in each other
d. determine by load on transformer secondary

8. A step up transformer increases
a. voltage
b. current
c. power
d. frequency

9. The primary and secondary windings of an two winding transformer
always have,
a. different no of turns
b. same size of copper wire
c. a common magnetic circuit
d. separate magnetic circuit

10. In a transformer the leakage flux of each winding is proportional to the
current in that winding because,
a. Ohm's law applies to the magnetic circuit
b. Leakage path do not saturate
c. the two windings are electrically isolated
d. mutual flux is confined to core

11. In a 2 winding transformer the emf per turn in secondary winding is
always ..... .the induced emf per turn in primary
a. equal to k times
b. equal to 1/k times
c. equal to
c. greater than

12. In a relation to a transformer the rayio 20/1 ; indicates that
a. there are 20 turns on primary and 1 turn on secondary
b. secondary voltage is 1/20 th of primary voltage
c. primary current is 20 times greater than secondary surrent
d. for every 20 turns on primary there is 1 turn on secondary

13. In performing short circuit test on transformer
a. high voltage side is usuallu short circuited
b. low volage is usually short circuited
c. any side is short circuited with preference
d. none of the above

14. The equivalent resistance of the primary of a transformer having K=5
and R1=0.1 ohmwhen referred to secondary becomes ..............ohm.
a. 0.5
b. 0.02
c. 0.004
d. 2.5

15. A trasformer hasnagative voltage regulation when it's load power is
a. zero
b. unity
c. leading
d. lagging

16. The primary reason why open circuit test is performed on the low
voltage winding of the transformer is that it
a. draws sufficiently large on load current for convinient reading
b. requires least voltage to perform the test
c. needs minimum power input
d. involves less core loss

17. No load test on a transformer is to measure its
a. copper losse
b. magnetising current
c. magnetising current and no load losses
d. efficiency of the transformer

18. The main purpose of performing open circuit test on a transformer is to
measure its
a. copper loss
b. core loss
c. total loss
d. insulation resistance

19. During short circuit test, iron loss of the transformer is neglisible
because
a. the entire input is just sufficient to meet cu losses only
b. fux produced is a small fraction of the normal flux
c. iron core becomes fully saturated
d. supply frequency is held constant

20. The iron loss of a transformer at 400Hz is 10 watt. Assuming that eddy
current and hysteresis losses vary as the squre of the flux density the iron
loss of the transformer at rated voltage but at 50 Hz would be ..............watts.
a. 80
b. 640
c. 1.25
d. 100

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Answered By StudyChaCha Member