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

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asked Mar 19, 2018 by anonymous

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asked Mar 19, 2018 by anonymous

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

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asked Mar 19, 2018 by anonymous

No-load current in a transformer?

Last answer: No-load current in a transformer lags behind the voltage by about 75°.

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No-load current of a transformer has?

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

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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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The inrush current of a transformer at no load is maximum if the supply voltage is switched on

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asked Mar 19, 2018 by anonymous

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

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

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asked Sep 27, 2017 by anonymous

in open circuit or no load test of transformer which side is low voltage side and which side is high voltage side?

Last answer: Primary side is low voltage side and secondary side is high voltage side.

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asked Apr 28, 2018 by anonymous

A transformer at 25 Hz develops 20 W hysteresis loss and 50 W eddy current loss. If the applied voltage and

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Last answer: A transformer at 25 Hz develops 20 W hysteresis loss and 50 W eddy current loss. If the applied voltage and frequency are doubled, the new core losses are 240 W

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

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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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asked Mar 19, 2018 by anonymous

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

Last answer: An ideal transformer will have maximum efficiency at a load such that copper loss equal to iron loss.

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asked Mar 27, 2018 by anonymous

The no-load current drawn by transformer is usually what per cent of the full-load current ?

Last answer: 5 to 8 percentage of full load current

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asked Sep 27, 2017 by anonymous

in open circuit or no load test of transformer which side is open circuited?

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

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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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asked Jun 18, 2018 by anonymous

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

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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

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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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asked Mar 19, 2018 by anonymous

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

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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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asked Mar 19, 2018 by anonymous

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

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asked Mar 19, 2018 by anonymous

A good voltage regulation of a transformer means?

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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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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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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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asked Mar 19, 2018 by anonymous

Iron loss of a transformer can be measured by?

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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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asked May 22, 2020 by anonymous

State why a transformer always have an efficiency of more than 90%.

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asked May 17, 2018 by anonymous

A single-phase transformer has no-load loss of 64 W, as obtained from an open circuit test. When a short-circuit

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Last answer: A single-phase transformer has no-load loss of 64 W, as obtained from an open circuit test. When a short-circuit test is performed on it with 90% of the rated currents flowing in its both ... measured loss is 81 W. The transformer has maximum efficiency when operated at 80.0% of the rated current

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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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asked May 17, 2018 by anonymous

Under no load condition, if the applied voltage to an induction motor is reduced from the rated voltage to

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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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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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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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asked Mar 19, 2018 by anonymous

The transformer laminations are insulated from each other by?

Last answer: The transformer laminations are insulated from each other by thin coat of varnish.

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70 views 1 answer

asked Mar 19, 2018 by anonymous

An ideal transformer is one which has?

Last answer: An ideal transformer is one which has no losses and magnetic leakage.

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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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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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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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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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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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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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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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asked Apr 5, 2018 by anonymous

A large transformer operating at no load draws an exciting current Io of 5A, when the primary is connected to...

A large transformer operating at no load draws an exciting current Io of 5A, when the primary is connected to a 120 V, 60 Hz source. From a wattmeter test, it is known that iron losses are equal to 180 W. Calculate the reactive power absorbed by the core. (A) 600 var (B) 572 var (C) 180 var (D) 360 var

Last answer: 572var

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asked May 8, 2018 by anonymous

The kVA rating of Three-phase transformer with Voltage = 200V and Current = 100A will be :

The kVA rating of Three-phase transformer with Voltage = 200V and Current = 100A will be : (A) 34.64 kVA (B) 75 kVA (C) 20 kVA (D) None of the above

Last answer: The kVA rating of Three-phase transformer with Voltage = 200V and Current = 100A will be : 34.64 kVA

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asked Mar 19, 2018 by anonymous

Which winding in a transformer has more number of turns ?

Last answer: High voltage winding in a transformer has more number of turns.

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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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anonymous · Answer 1 · 2018-03-19T21:46:36+0000

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

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

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