The power transformer is a constant?

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asked Mar 19, 2018 by anonymous

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asked Mar 19, 2018 by anonymous

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

Last answer: The maximum load that a power transformer can carry is limited by its voltage ratio.

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asked Mar 19, 2018 by anonymous

In a power or distribution transformer about 10 percent end turns are heavily insulated?

Last answer: In a power or distribution transformer about 10 percent end turns are heavily insulated to withstand the high voltage drop due to line surge produced by the shunting capacitance of the end turns.

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2

asked Apr 30, 2018 by anonymous

A transformer has negative voltage regulation when its load power factor is

A transformer has negative voltage regulation when its load power factor is (1) Zero (2) Unity (3) Leading (4) Lagging

Last answer: Leading

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1.0k views 2 answers

3

asked May 8, 2018 by anonymous

What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to

What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage: (A) Eddy Current and Hysteresis losses will be excessive (B) Current will be too much high (C) Transformer may start to smoke and burn (D) No effect

Last answer: What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage: (A) Eddy Current and Hysteresis losses will be ... will be too much high (C) Transformer may start to smoke and burn (D) No effect

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484 views 1 answer

4

asked Apr 27, 2018 by anonymous

To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ?

Last answer: To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ? Δ-Δ connection

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317 views 1 answer

5

asked Mar 19, 2018 by anonymous

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.

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102 views 1 answer

6

asked Mar 19, 2018 by anonymous

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

Last answer: For a transformer, operating at constant load current, maximum efficiency will occur at unity power factor.

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89 views 1 answer

7

asked Mar 11, 2018 by anonymous

Explain transformer isolated drive circuits providing both signal and power.

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8

asked Mar 19, 2018 by anonymous

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.

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9

asked Mar 19, 2018 by anonymous

Efficiency of a power transformer is of the order of?

Last answer: The efficiency of a power transformer is of the order of 98 percent.

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10

asked Jul 27, 2019 by anonymous

State and justify which of the following two transformers is better: Transformer A = 4% voltage regulation Transformer B = 6% voltage regulation

Last answer: Transformer A with 4% voltage regulation is better. Justification: Voltage regulation refers to the percentage change in secondary voltage when load is changed from no-load to full-load with primary voltage ... 4% voltage regulation, which is less as compared to 6% of transformer B, it is better.

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11

asked Mar 19, 2018 by anonymous

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.

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83 views 1 answer

12

asked Mar 19, 2018 by anonymous

The maximum efficiency of a distribution transformer is?

Last answer: The maximum efficiency of a distribution transformer is at 50% full load.

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56 views 1 answer

13

asked Mar 19, 2018 by anonymous

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.

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272 views 1 answer

14

asked Mar 19, 2018 by anonymous

The thickness of laminations used in a transformer is usually?

Last answer: The thickness of laminations used in a transformer is usually 0.4 mm to 0.5 mm.

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64 views 1 answer

15

asked Mar 19, 2018 by anonymous

The function of conservator in a transformer is?

Last answer: conservator or a reservoir tank for insulating oil in transformer which used for balanced the onload oil level with help of oil level indicator which mount on middle part of reservoir tank.

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104 views 3 answers

16

asked Mar 19, 2018 by anonymous

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

Last answer: The magnetising current of a transformer is usually small because it has small air gap.

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60 views 1 answer

17

asked Mar 19, 2018 by anonymous

The full-load copper loss of a transformer is 1600 W At half-load, the copper loss will be?

Last answer: The full-load copper loss of a trans¬former is 1600 W. At half-load, the copper loss will be 400 W.

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66 views 1 answer

18

asked Mar 19, 2018 by anonymous

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

Last answer: The value of flux involved in the e.m.f. equation of a transformer is maximum value.

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123 views 1 answer

19

asked Mar 19, 2018 by anonymous

The function of breather in a transformer is?

Last answer: The function of breather in a transformer is to arrest flow of moisture when outside air enters the transformer.

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100 views 1 answer

20

asked Mar 19, 2018 by anonymous

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

Last answer: The secondary of a current transformer is always short-circuited under operating conditions because it avoids core saturation and high voltage induction.

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74 views 1 answer

21

asked Mar 19, 2018 by anonymous

The noise produced by a transformer is termed as?

Last answer: The noise produced by a transformer is termed as hum.

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76 views 1 answer

22

asked Mar 19, 2018 by anonymous

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

Last answer: If a transformer is continuously operated the maximum temperature rise will occur in windings.

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55 views 1 answer

23

asked Mar 19, 2018 by anonymous

The hum in a transformer is mainly attributed to?

Last answer: The hum in a transformer is mainly attributed to magnetostriction.

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86 views 1 answer

24

asked Mar 19, 2018 by anonymous

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

Last answer: The efficiency of a transformer, under heavy loads, is comparatively low because copper loss becomes high in proportion to the output.

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64 views 1 answer

25

asked Mar 19, 2018 by anonymous

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

Last answer: The voltage transformation ratio of a transformer is equal to the ratio of secondary induced e.m.f. to primary induced e.m.f.

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92 views 1 answer

26

asked Mar 19, 2018 by anonymous

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

Last answer: If a transformer is switched on to a voltage more than the rated voltage its power factor will deteriorate.

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70 views 1 answer

27

asked Mar 19, 2018 by anonymous

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

Last answer: In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of less than 15A.

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90 views 1 answer

28

asked Mar 19, 2018 by anonymous

Noise level test in a transformer is a?

Last answer: Noise level test in a transformer is a type test.

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70 views 1 answer

29

asked Mar 19, 2018 by anonymous

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

Last answer: When a given transformer is run at its rated voltage but reduced frequency, its core flux density is increased.

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76 views 1 answer

30

asked Mar 19, 2018 by anonymous

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.

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97 views 1 answer

31

asked Mar 19, 2018 by anonymous

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

Last answer: The open-circuit test in a transformer is used to measure

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254 views 2 answers

32

asked Mar 19, 2018 by anonymous

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

Last answer: A no-load test is performed on a transformer to determine magnetizing current and loss.

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84 views 1 answer

33

asked Mar 19, 2018 by anonymous

A ferro resonant transformer regulation is also known as?

Last answer: A ferro resonant transformer regulation is also known as constant current transformer.

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69 views 1 answer

34

asked Apr 28, 2020 by anonymous

Even at no-load, a transformer draws current from the mains. Why?

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35

asked Mar 19, 2018 by anonymous

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.

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132 views 1 answer

36

asked Mar 19, 2018 by anonymous

The no load current in a transformer lags behind the applied voltage by an angle of about?

Last answer: The no load current in a transformer lags behind the applied voltage by an angle of about 75°.

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77 views 1 answer

37

asked Mar 19, 2018 by anonymous

In a transformer the tappings are generally provided on?

Last answer: In a transformer, the tappings are generally provided on low voltage side.

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53 views 1 answer

38

asked Mar 19, 2018 by anonymous

The main reason for generation of harmonics in a transformer could be?

Last answer: The main reason for generation of harmonics in a transformer could be saturation of core.

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69 views 1 answer

39

asked Mar 19, 2018 by anonymous

The leakage flux in a transformer depends upon?

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

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103 views 1 answer

40

asked Mar 19, 2018 by anonymous

The size of a transformer core will depend on?

Last answer: The size of a transformer core will depend on frequency and area of the core.

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63 views 1 answer

41

asked Mar 19, 2018 by anonymous

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

Last answer: In a transformer the resistance between its primary and secondary should be infinity.

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96 views 1 answer

42

asked Mar 19, 2018 by anonymous

The path of magnetic flux in a transformer should have?

Last answer: The path of magnetic flux in a transformer should have low reluctance.

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258 views 1 answer

43

asked May 15, 2020 by anonymous

What is the use of transformer?

Last answer: The use of transformer is to do lower or raise the voltage or currents in an electrical circuit. That's quite so simple.

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138 views 1 answer

44

asked Mar 19, 2018 by anonymous

An ideal transformer has infinite values of primary and secondary inductances. The statement is?

Last answer: An ideal transformer has infinite values of primary and secondary inductances. The statement is false.

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132 views 1 answer

45

asked Mar 19, 2018 by anonymous

Gas is usually not liberated due to dissociation of transformer oil unless the oil temperature exceeds?

Last answer: Gas is usually not liberated due to dissociation of transformer oil unless the oil temperature exceeds 150°C.

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104 views 1 answer

46

asked Mar 19, 2018 by anonymous

The core used in high frequency transformer is usually?

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

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48 views 1 answer

47

asked Mar 19, 2018 by anonymous

Atmospheric temperature during day and night is taken care of by which part of the transformer?

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

Last answer: The changes in the volume of transformer cooling oil due to the variation of atmospheric temperature during day and night is taken care of by conservator.

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44 views 1 answer

48

asked Mar 19, 2018 by anonymous

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.

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102 views 1 answer

49

asked Mar 19, 2018 by anonymous

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

Last answer: Part of the transformer which is most subject to damage from overheating is winding insulation.

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74 views 1 answer

50

anonymous · Answer 1 · 2018-03-19T21:36:40+0000

answered Mar 19, 2018 by anonymous

The power transformer is a constant main flux device.

The power transformer is a constant?

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