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March 29th, 2017, 10:50 AM
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Join Date: Mar 2012
Re: IBPS Specialist Officer Electrical Question Paper

As you Asking for the Question Paper of the Electrical Engineering of the IBPS Specialist Officer the Question Paper is As Follow


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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

. 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


. The voltage applied to the HV side of a transformer durng short circuit test is 2% of its rated voltage. The core loss willbe.............% of the rated core loss
a. 4
b. 0.4
c. 0.25
d. 0.04

. Trasformer are rated in kVA instead of kW because
a. load power factor is often not known
b. kVA is fixed whereas kW depends on load PF
c. total transformer loss depends on the volt ampere
d. it has become customary


. When a 400 Hs transformer is operated at 50 Hz,it's kVA rating is,
a. reduced to 1/8
b.incresed 8 times
c. unaffected
d. incresed 64 times

. At relatively light loads, transformer efficiency is low because,
a. secondary output is low
b. transformer losses are high
c. fixed losses are high in proportion to the output
d. cu loss is small

A 200 kVA transformer has an iron loss of 1kW and full load copper
loss of 2 kW. Its load kVA corresponding to maximumefficiency
is.......kVA.
a. 100
b. 141.4
c. 50
d. 200

. If Cu loss of a transformer at 7/8th full load is 4900 W, then its full load
cu loss will be..........watt.
a. 5600
b. 6400
c. 375
d. 429

. The ordinary efficiency of a given transformer is maximum when
a. it runs at half load
b. it runs at full load
c. its cu loss equals iron loss
d. it runs slightly overload

The o/p current corresponding to maximum efficiency for a transformer
having core loss of 100 watt and equivalent resistance reffered to secondary
of 0.25 ohm is .............ampere.
a. 20
b. 25
c. 5
d. 400


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