[53] The iron loss of the transformer is negligible during short circuit test because A. The entire input is just sufficient to meet Cu losses only B. Flux produced is a small fraction of the normal flux C. Iron core becomes fully saturated D. Supply frequency is held constant

[53] The iron loss of the transformer is negligible during short circuit test because
A. The entire input is just sufficient to meet Cu losses only
B. Flux produced is a small fraction of the normal flux
C. Iron core becomes fully saturated
D. Supply frequency is held constant
by

1 Answer

Answer :

B. Flux produced is a small fraction of the normal flux
by

Related questions

During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer

Description : During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer

Last Answer : C) the voltage applied on primary side is low

During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer

Description : During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer

Last Answer : C) the voltage applied on primary side is low

During short circuit test iron losses are negligible because?

Description : During short circuit test iron losses are negligible because?

Last Answer : During short circuit test iron losses are negligible because the voltage applied on primary side is low.

48.During light loads, the transformer efficiency is low because A. Secondary output is low B. Transformer losses are high C. Fixed loss is high in proportion to the output D. Cu loss is small

Description : 48.During light loads, the transformer efficiency is low because A. Secondary output is low B. Transformer losses are high C. Fixed loss is high in proportion to the output D. Cu loss is small

Last Answer : C. Fixed loss is high in proportion to the output

64)During the short-circuit test on a small transformer the frequency is increased from 50-200Hz. The copper losses will increase by a factor of A. 16 B. 4 C. 1 D. 1/4

Description : 64)During the short-circuit test on a small transformer the frequency is increased from 50-200Hz. The copper losses will increase by a factor of A. 16 B. 4 C. 1 D. 1/4

Last Answer : A) 16

49 The open circuit test is carried out in a transformer to find the A. Cu loss B. Core loss C. Total loss D. Insulation resistance

Description : 49 The open circuit test is carried out in a transformer to find the A. Cu loss B. Core loss C. Total loss D. Insulation resistance

Last Answer : B. Core loss

[75] Two transformers are connected in parallel. These transformers do not have equal percentage impedance which results A. Short-circuiting of the secondaries B. Power factor of one of the transformers is leading while that of the other lagging C. Transformers having higher copper losses will have negligible core losses D. Loading of the transformers not in proportion to their kVA ratings.

Description : [75] Two transformers are connected in parallel. These transformers do not have equal percentage impedance which results A. Short-circuiting of the secondaries B. Power factor of one of the ... have negligible core losses D. Loading of the transformers not in proportion to their kVA ratings.

Last Answer : D. Loading of the transformers not in proportion to their kVA ratings

43 The purpose of providing an iron core in a transformer is to A.Provide support to windings B. Reduce hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses

Description : 43 The purpose of providing an iron core in a transformer is to A.Provide support to windings B. Reduce hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses

Last Answer : C. Decrease the reluctance of the magnetic path

7 The main advantage of auto transformer over a two winding transformer is A. Hysteresis losses are reduced B. Saving in winding material C. Copper losses are negligible D. Eddy losses are totally eliminated

Description : 7 The main advantage of auto transformer over a two winding transformer is A. Hysteresis losses are reduced B. Saving in winding material C. Copper losses are negligible D. Eddy losses are totally eliminated

Last Answer : A) hysteresis losses is reduced

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

Last Answer : If the supply frequency to the transformer is increased, the iron loss will increase.

27] In a transformer, the leakage flux of each winding is proportional to the current in that winding because A. Ohm's law applies to magnetic circuits B. Leakage paths do no saturate C. the two windings are electrically isolated D. mutual flux is confined to the core

Description : 27] In a transformer, the leakage flux of each winding is proportional to the current in that winding because A. Ohm's law applies to magnetic circuits B. Leakage paths do no saturate C. the two windings are electrically isolated D. mutual flux is confined to the core

Last Answer : B. Leakage path do not saturate

Why are iron losses considered as constant losses in transformer?

Description : Why are iron losses considered as constant losses in transformer?

Last Answer : Iron losses depend on supply frequency and flux density in the core. For all normal operations, the frequency of flux reversals which is same as supply frequency is constant and the value of flux density ... . Hence iron losses remain constant under all load conditions. i-e from no-load to full-load

72 Harmonics in transformer result in A. Increased core losses B. Increased I2R losses C. Magnetic interference with communication circuits D. All of the above

Description : 72 Harmonics in transformer result in A. Increased core losses B. Increased I2R losses C. Magnetic interference with communication circuits D. All of the above

Last Answer : D. All of the above

45 The function of conservator in a transformer is A. To protect against internal fault B. To reduce copper as well as core losses C. To cool the transformer oil D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings

Description : 45 The function of conservator in a transformer is A. To protect against internal fault B. To reduce copper as well as core losses C. To cool the transformer oil D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings

Last Answer : D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings

8 The transformer core is laminated to A. Reduce the copper losses B. Reduce the core losses C. Reduce the eddy current losses D. None of the above

Description : 8 The transformer core is laminated to A. Reduce the copper losses B. Reduce the core losses C. Reduce the eddy current losses D. None of the above

Last Answer : C. Reduce the eddy current losses

I13) In an ideal transformer A. windings have no resistance B. core has no losses C. core has infinite permeability D. all of the above

Description : 13) In an ideal transformer A. windings have no resistance B. core has no losses C. core has infinite permeability D. all of the above

Last Answer : D. All of the above

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

Description : Reduction in core losses and increase in permeability are obtained with transformer employing?

Last Answer : Reduction in core losses and increase in permeability are obtained with transformer employing core built-up of laminations of cold rolled grain oriented steel.

46 The core used in high frequency transformer is usually A. Copper core B. Cost iron core C. Air core D.Mid steel core

Description : 46 The core used in high frequency transformer is usually A. Copper core B. Cost iron core C. Air core D.Mid steel core

Last Answer : C. Air core

12] Which is not the basic element of the transformer? A. core B. primary winding C. secondary winding D. mutual flux

Description : 12] Which is not the basic element of the transformer? A. core B. primary winding C. secondary winding D. mutual flux

Last Answer : D. Mutual flux

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

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

Last Answer : In an actual transformer the iron loss remains practically constant from no load to full load because core flux remains practically constant.

At the liquid limit a) The soil just begins to crumble when rolled into a thread b) The shearing strength against flowing is negligible c) The shearing strength against flowing is a small but definite* d) The soil will not get fully saturated

Description : At the liquid limit a) The soil just begins to crumble when rolled into a thread b) The shearing strength against flowing is negligible c) The shearing strength against flowing is a small but definite* d) The soil will not get fully saturated

Last Answer : c) The shearing strength against flowing is a small but definite

[31] With both S1 and S2 open, the core flux waveform will be [GATE 2009] A. a sinusoidal at fundamental frequency B. flat-topped with third harmonic C. peaky with third-harmonic D. none of these

Description : [31] With both S1 and S2 open, the core flux waveform will be [GATE 2009] A. a sinusoidal at fundamental frequency B. flat-topped with third harmonic C. peaky with third-harmonic D. none of these

Last Answer : B. Flat topped with third harmonic

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

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

Last Answer : In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are hysteresis and eddy current losses.

42 The efficiency of a transformer will be maximum when A. copper losses = hysteresis losses B. Hysteresis losses = eddy current losses C. Eddy current losses = copper losses D. Copper losses = iron losses

Description : 42 The efficiency of a transformer will be maximum when A. copper losses = hysteresis losses B. Hysteresis losses = eddy current losses C. Eddy current losses = copper losses D. Copper losses = iron losses

Last Answer : D. Copper losses = iron losses

66 While conducting short-circuit test on a transformer the following side is short circuited A. High voltage side B. low voltage side C. primary side D. secondary side

Description : 66 While conducting short-circuit test on a transformer the following side is short circuited A. High voltage side B. low voltage side C. primary side D. secondary side

Last Answer : B. Low voltage side

30 In performing the short circuit test of a transformer A. high voltage is usually short circuited B. low voltage side is usually short circuited C. any side is short circuited with preference D. none of the above

Description : 30 In performing the short circuit test of a transformer A. high voltage is usually short circuited B. low voltage side is usually short circuited C. any side is short circuited with preference D. none of the above

Last Answer : B. Low voltage side is usually short circuited

what is short circuit test in transformer?

Last Answer : In short circuit test of transformer the low voltage side is short circuited . On high voltage side the voltmeter is connected in parallel and ammeter in series and also a wattmeter is ... circuit test is done for determining impedance and losses. In this test iron losses is neglected.

The core used in high frequency transformer is usually?

Last Answer : The core used in high frequency transformer is usually air core .

19 .Transformer cores are built up from laminations rather than from solid metal so that A. Oil penetrates the core more easily B. Eddy current loss is reduced C. Less lamination is required for the windings D. Turn ratio is higher than voltage ratio

Description : 19 Transformer cores are built up from laminations rather than from solid metal so that A. Oil penetrates the core more easily B. Eddy current loss is reduced C. Less lamination is required for the windings D. Turn ratio is higher than voltage ratio

Last Answer : B. Eddy current loss is reduced

Which of the following properties is not necessarily desirable in the material for transformer core? A. Mechanical strength B. Low hysteresis loss C. High thermal conductivity D. High permeability

Description : Which of the following properties is not necessarily desirable in the material for transformer core? A. Mechanical strength B. Low hysteresis loss C. High thermal conductivity D. High permeability

Last Answer : C) high thermal conductivity

A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The

Description : A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is

Last Answer : A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is 0.707

The purpose of providing an iron core in a transformer is to?

Last Answer : The purpose of providing an iron core in a transformer is to decrease the reluctance of the magnetic path.

The purpose of providing iron core in a step-up transformer is?

Last Answer : The purpose of providing iron core in a step-up transformer is to decrease the magnitude of magnetizing current.

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

Description : When secondary of a current transformer is open-circuited its iron core will be?

Last Answer : When secondary of a current transformer is open-circuited its iron core will be hot because of heavy iron losses taking place in it due to high flux density.

An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to

Description :  An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to secondary turn’s ratio 12:1. The peak inverse voltage is A) 8.62 V B) 12 V C) 19.17 V D) 27.11 V 

Last Answer :  An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to secondary turn’s ratio 12:1. The peak inverse voltage is A) 8.62 V B) 12 V C) 19.17 V D) 27.11 V 

Why not reduce the noise in the core by reducing the amount of flux?

Description : Why not reduce the noise in the core by reducing the amount of flux?

Last Answer : Transformer voltages are fixed by system requirements. The ratio of these voltages to the number of turns in the winding determines the amount of magnetization. This ratio of voltage to turns is determined ... flux at the normal voltage is fixed. This also fixes the level of noise and vibration.

During open circuit test of a transformer?

Description : During open circuit test of a transformer?

Last Answer : During open circuit test of a transformer primary is supplied rated voltage.

What are the transformer losses?

Description : What are the transformer losses?

Last Answer : Answer: TRANSFORMER LOSSES - There are mainly two kinds of losses in a transformer namely 1. Copper loss (ohmic loss) and 2.magnetic loss (core loss). Copper losses are caused by the ... ohmic loss the following two losses are also present in the transformer stray load loss and dielectric loss.

Explain about the losses in Transformer?

Description : Explain about the losses in Transformer?

Last Answer : TRANSFORMER LOSSES - Transformer losses have two sourcescopper loss and magnetic loss. Copper losses are caused by the resistance of the wire (I2R). Magnetic losses are caused by eddy currents ... current. Eddy-current loss, however, is different for each frequency passed through the transformer.

Explain about the open and short circuit tests on transformer?

Description : Explain about the open and short circuit tests on transformer?

Last Answer : A. Open circuit test (No load test) and short circuit test (full load test) are performed on a transformer to determine (i) Equivalent circuit of transformer (ii) Voltage ... determine copper loss in transformer at full load and parameters of approximate equivalent circuit of transformer.

The short circuit in any winding of the transformer is the result of?

Last Answer : The short circuit in any winding of the transformer is the result of impulse voltage.

A transformer cannot raise or lower the voltage of a D.C. supply because?

Last Answer : A transformer cannot raise or lower the voltage of a D.C. supply because Faraday's laws of electromagnetic induction are not valid since the rate of change of flux is zero.

68 The path of a magnetic flux in a transformer should have A. High resistance B. High reluctance C. Low resistance D. Low reluctance

Description : 68 The path of a magnetic flux in a transformer should have A. High resistance B. High reluctance C. Low resistance D. Low reluctance

Last Answer : D. Low reluctance

38] In a transformer the energy is conveyed from primary to secondary? A. Through cooling coil B. Through air C. By the flux D. None of the above

Description : 38] In a transformer the energy is conveyed from primary to secondary? A. Through cooling coil B. Through air C. By the flux D. None of the above

Last Answer : C. By the flux

6 The value of flux involved in the emf equation of a transformer is A. rms value B. rms value C. Maximum value D. Instantaneous value

Description : 6 The value of flux involved in the emf equation of a transformer is A. rms value B. rms value C. Maximum value D. Instantaneous value

Last Answer : C) maximum value

The use of higher flux density in the transformer design?

Last Answer : The use of higher flux density in the transformer design reduces weight per kVA.

The leakage flux in a transformer depends upon?

Last Answer : The leakage flux in a transformer depends upon load current.

The value of flux involved in the e.m.f. equation of a transformer is ?

Last Answer : Power on primary and secondary side of transformer A. Remains Approximately constant B. Are always different C. Is always 100kVA D. None of these