Transformers Mcqs – (Electrical Engineering) MCQs Latest For FPSC, PPSC, NTS, KPPSC, SPSC & Other Tests

Transformers Mcqs – (Electrical Engineering) MCQs Latest For FPSC, PPSC, NTS, KPPSC, SPSC & Other Tests

Transformers Mcqs - (Electrical Engineering) MCQs Latest For FPSC, PPSC, NTS, KPPSC, SPSC & Other Tests
Transformers Mcqs

Transformers Mcqs “. Tab this page to check “Latest Transformers MCQs” for the preparation of competitive mcqs, FPSC mcqs, PPSC mcqs, SPSC mcqs, KPPSC mcqs, AJKPSC mcqs, BPSC mcqs, NTS mcqs, PTS mcqs, OTS mcqs, Atomic Energy mcqs, Pak Army mcqs, Pak Navy mcqs, CTS mcqs, ETEA mcqs and others. The most occurred mcqs of Transformers in past papers. Past papers of Transformers mcqs. Past papers of Transformers MCQs. Transformers Mcqs are the necessary part of any competitive / job related exams. The Transformers mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related Transformers mcqs. The Important series of Transformers Mcqs are given below:

Which of the following statements regarding an idel single-phase transformer having a turn ratio of 1 : 2 and drawing a current of 10 A from 200 V A.C. supply is incorrect?

A. Its secondary voltage is 400 V
B. Its secondary current is 5 A
C. Its rating is 2 kVA
D. Its secondary current is 20 A
E. It is a step-up transformer

In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are__________?

A. hysteresis and eddy current losses
B. copper losses
C. friction and windage losses
D. none of the above

Losses which occur in rotating electric machines and do not occur in transformers are___________?

A. friction and windage losses
B. copper losses
C. hysteresis and eddy current losses
D. magnetic losses

For given applied voltage, with the increase in frequency of the applied voltage?

A. eddy current loss will increase
B. eddy current loss will decrease
C. eddy current loss will remain unchanged
D. none of the above

In a power or distribution transformer about 10 per cent end turns are heavily insulated__________?

A. to withstand the high voltage drop due to line surge produced by the shunting capacitance of the end turns
B. to reflect the line surge and save the winding of a transformer from damage
C. to absorb the line surge voltage and save the winding of transformer from damage
D. none of the above

Reduction in core losses and increase in permeability are obtained with transformer employing__________?

A. core built-up of laminations of cold rolled grain oriented steel
B. either of the above
C. core built-up of laminations of hot rolled sheet
D. none of the above

The noise produced by a transformer is termed as_______________________?

A. ringing
B. hum
C. zoom
D. buzz

Which of the following parts of a transformer is visible from outside ?

A. Bushings
B. Primary winding
C. Core
D. Secondary winding

Which of the following insulating materials can withstand the highest temperature safely ?

A. Asbestos
B. Cellulose
C. Mica
D. Glass fibre

The efficiency of two identical transformers under load conditions can be determined by_______________?

A. open circuit test
B. back-to-back test
C. short-circuit test
D. any of the above

Which of the following acts as a protection against high voltage surges due to lightning and switching ?

A. Horn gaps
B. Breather
C. Thermal overload relays
D. Conservator

A good voltage regulation of a transformer means________________?

A. output voltage fluctuation from no load to full load is least
B. difference between primary and secondary voltage is least
C. output voltage fluctuation with power factor is least
D. difference between primary and secondary voltage is maximum

Which of the following protection is normally not provided on small distribution transformers ?

A. Overcurrent protection
B. Buchholz relay
C. Overfluxing protection
D. All of the above

For a transformer, operating at constant load current, maximum efficiency will occur at______________?

A. 0.8 lagging power factor
B. 0.8 leading power factor
C. zero power factor
D. unity power factor

A Transformer transforms____________?

A. current
B. voltage
C. current and voltage
D. power

A transformer can have regulation closer to zero___________?

A. on overload
B. on full-load
C. on leading power factor
D. on zero power factor

In a transformer the resistance between its primary and secondary should be_____________?

A. 10 Q
B. zero
C. 1000 Q
D. infinity

The secondary of a current transformer is always short-circuited under operating conditions because it____________________?

A. avoids core saturation and high voltage induction
B. protects the primary circuit
C. is safe to human beings
D. none of the above

A shell-type transformer has_________?

A. negligibly hysteresis losses
B. reduced magnetic leakage
C. high eddy current losses
D. none of the above

Natural air coo ling is generally restricted for transformers up to__________?

A. 1.5 MVA
B. 15 MVA
C. 5 MVA
D. 50 MVA

The size of a transformer core will depend on__________?

A. area of the core
B. frequency
C. flux density of the core material
D. A. and B. both

The secondary winding of which of the following transformers is always kept closed?

A. Step-down transformer
B. Step-up transformer
C. Potential transformer
D. Current transformer

The function of breather in a transformer is___________?

A. to cool the coils during reduced load
B. to provide oxygen inside the tank
C. to cool the transformer oil
D. to arrest flow of moisture when outside air enters the transformer

The efficiencies of transformers compared with that of electric motors of the same power are____________?

A. much smaller
B. about the same
C. much higher
D. somewhat smaller
E. none of the above

The transformer oil should have _______ volatility and _______ viscosity?

A. low,low
B. low,high
C. high,high
D. high,low

In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of_________________?

A. less than 15 A
B. 15 A
C. more than 15 A
D. none of the above

For the parallel operation of single phase transformers it is necessary that they should have___________?

A. same kVA rating
B. same polarity
C. same efficiency
D. same number of turns on the secondary side.

Minimum voltage regulation occurs when the power factor of the load is_____________?

A. lagging
B. unity
C. leading
D. zero

Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is_________________?

A. approximately equal to one
B. great than one
C. less than one
D. none of the above

Short circuit test on transformers is conducted to determine____________?

A. core losses
B. copper losses
C. hysteresis losses
D. eddy current losses

If a transformer is switched on to a voltage more than the rated voltage______________?

A. its power factor will deteriorate
B. its power factor will remain unaffected
C. its power factor will increase
D. its power factor will be zero

Open circuit test on transformers is conducted to determine____________?

A. copper losses
B. hysteresis losses
C. core losses
D. eddy current losses

Part of the transformer which is most subject to damage from overheating is_____________?

A. copper winding
B. iron core
C. winding insulation
D. frame or case
E. transformer tank

During open circuit test of a transformer:

A. primary is supplied rated voltage
B. primary is supplied rated kVA
C. primary is supplied current at reduced voltage
D. primary is supplied full-load current

The voltage transformation ratio of a transformer is equal to the ratio of_______________?

A. secondary current to primary current
B. primary turns to secondary turns
C. secondary induced e.m.f. to primary induced e.m.f
D. secondary terminal voltage to primary applied voltage

A no-load test is performed on a transformer to determine_______________?

A. copper loss
B. core loss
C. efficiency
D. magnetising current
E. magnetising current and loss

Which type of winding is used in 3 phase shell-type transformer?

A. Cylindrical type
B. Sandwich type
C. Circular type
D. Rectangular type

An open-circuit test on a transformer is conducted primarily to measure______________?

A. copper loss
B. insulation resistance
C. core loss
D. total loss
E. efficiency
F. none of the above

The transformer lamination’s are insulated from each other by____________?

A. paper
B. thin coat of varnish
C. mica strip
D. any of the above

When secondary of a current transformer is open-circuited its iron core will be__________?

A. hot because of heavy iron losses taking place in it due to high flux density
B. cool as there is no secondary current
C. hot because primary will carry heavy current
D. none of above will happen

The efficiency of a transformer, under heavy loads, is comparatively low because_______________?

A. copper loss becomes high in proportion to the output
B. voltage drop both in primary and secondary becomes large
C. iron loss is increased considerably
D. secondary output is much less as compared to primary input

The maximum load that a power transformer can carry is limited by its________________?

A. dielectric strength of oil
B. temperature rise
C. voltage ratio
D. copper loss

The hum in a transformer is mainly attributed to______________?

A. oil in the transformer
B. load changes
C. magnetostriction
D. mechanical vibrations

Which of the following is the most likely source of harmonics in a transformer ?

A. Overload
B. poor insulation
C. loose connections
D. Core saturation

If a transformer is continuously operated the maximum temperature rise will occur in_______________?

A. tank
B. windings
C. core
D. any of the above

Iron loss of a transformer can be measured by____________?

A. low power factor wattmeter
B. frequency meter
C. unity power factor wattmeter
D. any type of wattmeter

Which of the following loss in a transformer is zero even at full load ____________?

A. Eddy current loss
B. Friction loss
C. Core loss
D. Hysteresis loss

Negative voltage regulation is indicative that the load is___________?

A. capacitive only
B. inductive or resistive
C. inductive only
D. none of the above

Helical coils can be used on___________________?

A. low voltage side of high kVA transformers
B. high voltage side of small capacity transformers
C. high frequency transformers
D. high voltage side of high kVA rating transformers

If the supply frequency to the transformer is increased,”the iron loss will__________?

A. decrease
B. not change
C. increase
D. any of the above

Which of the following is not a routine test on transformers ?

A. Impedance test
B. Core insulation voltage test
C. Radio interference test
D. Polarity test

A transformer can have zero voltage regulation at______________?

A. leading power factor
B. unity power factor
C. lagging power factor
D. zero power factor

An ideal transformer will have maximum efficiency at a load such that?

A. copper loss = iron loss
B. copper loss > iron loss
C. copper loss < iron loss
D. none of the above

Noise level test in a transformer is a______________?

A. routine test
B. special test
C. type test
D. none of the above

In an actual transformer the iron loss remains practically constant from no load to full load because:____________?

A. permeability of transformer core remains constant
B. value of transformation ratio remains constant
C. core flux remains practically constant
D. primary voltage remains constant
C. secondary voltage remains constant

The path of the magnetic flux in transformer should have____________?

A. high resistance
B. low reactance
C. high reluctance
D. low resistance

When a given transformer is run at its rated voltage but reduced frequency, its____________?

A. iron losses are reduced
B. flux density remains unaffected
C. core flux density is reduced
D. core flux density is increased

Which of the following properties is not necessarily desirable for the material for transformer core ?

A. High permeability
B. Low hysteresis loss
C. High thermal conductivity
D. Adequate mechanical strength

The leakage flux in a transformer depends upon______________?

A. load current
B. load current, voltage and frequency
C. load current and voltage
D. load current, voltage, frequency and power factor

An ideal transformer is one which has_____________?

A. no losses and magnetic leakage
B. core of stainless steel and winding of pure copper metal
C. a common core for its primary and secondary windings
D. interleaved primary and secondary windings
E. none of the above

Which of the following does not change in an ordinary transformer ?

A. Frequency
B. Current
C. Voltage
D. Any of the above

The changes in volume of transformer cooling oil due to variation of atmospheric temperature during day and night is taken care of by which part of transformer?

A. Conservator
B. Bushings
C. Breather
D. Buchholz relay

The magnetising current of a transformer is usually small because it has___________?

A. small air gap
B. laminated silicon steel core
C. large leakage flux
D. fewer rotating parts

Buchholz’s relay gives warning and protection against_________________?

A. electrical fault inside the transformer itself
B. for both outside and inside faults
C. electrical fault outside the transformer in outgoing feeder
D. none of the above

Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in____________?

A. transformers having higher copper losses will have negligible core losses
B. power factor of one of the transformers is leading while that of the other lagging
C. short-circuiting of the secondaries
D. loading of the transformers not in proportion to their kVA ratings

During short circuit test iron losses are negligible because of _____________?

A. the voltage on secondary side does not vary
B. the current on secondary side is negligible
C. the voltage applied on primary side is low
D. full-load current is not supplied to the transformer

Which of the following is the main advantage of an auto-transformer over a two winding transformer?

A. Copper losses are negligible
B. Saving in winding material
C. Hysteresis losses are reduced
D. Eddy losses are totally eliminated

Power transformers are generally designed to have maximum efficiency around__________?

A. half-load
B. no-load
C. near full-load
D. 10% overload

Which winding of the transformer has less cross-sectional area?

A. Secondary winding
B. Primary winding
C. Low voltage winding
D. High voltage winding

Silicon steel used in lamination’s mainly reduces___________?

A. hysteresis loss
B. copper losses
C. eddy current losses
D. all of the above

Transformers Mcqs – (Electrical Engineering) MCQs Latest For FPSC, PPSC, NTS, KPPSC, SPSC & Other Tests

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