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No-load current in a transformer?
asked
Mar 19, 2018
by
anonymous
transformer
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1
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answered
Mar 19, 2018
by
anonymous
No-load current in a transformer
lags behind the voltage by about 75°.
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Related questions
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°.
transformer
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78
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1
answer
asked
Apr 28, 2020
by
anonymous
Even at no-load, a transformer draws current from the mains. Why?
Even at no-load, a transformer draws current from the mains. Why?
even
at
no-load
a
transformer
draws
current
from
the
mains
why
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1
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73
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0
answers
asked
Mar 19, 2018
by
anonymous
No-load current of a transformer has?
Last answer:
No-load current of a transformer has small magnitude and low power factor.
transformer
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45
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1
answer
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.
transformer
iron
loss
constant
load
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77
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1
answer
asked
Mar 19, 2018
by
anonymous
A no-load test is performed on a transformer to determine?
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.
no-load
test
transformer
determine
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84
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1
answer
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?
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.
step-down
transformer
load
current
change
supply
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1
answer
asked
Apr 30, 2018
by
anonymous
The inrush current of a transformer at no load is maximum if the supply voltage is switched on
The inrush current of a transformer at no load is maximum if the supply voltage is switched on (1) at peak voltage value (2) at zero voltage value (3) at half voltage value (4) at 0.866 time voltage value
Last answer:
At 0.866 time voltage value
inrush
current
transformer
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80
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2
answers
asked
Mar 19, 2018
by
anonymous
For a transformer, operating at constant load current, maximum efficiency will occur at?
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.
transformer
operating
constant
load
current
maximum
efficiency
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89
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1
answer
asked
Mar 19, 2018
by
anonymous
In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are?
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.
transformer
voltage
losses
constant
load
changes
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103
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1
answer
asked
Sep 27, 2017
by
anonymous
in open circuit or no load test of transformer which side is open circuited?
Last answer:
High Voltage side is open circuited.
transformer
open
circuit
test
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91
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1
answer
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.
open
circuit
test
transformer
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1
answer
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.
transformer
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1
answer
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.
ideal
transformer
maximum
efficiency
load
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96
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1
answer
asked
Mar 19, 2018
by
anonymous
The maximum load that a power transformer can carry is limited by its?
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.
maximum
load
power
transformer
carry
limited
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104
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1
answer
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.
transformer
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1
answer
asked
Mar 19, 2018
by
anonymous
When secondary of a current transformer is open-circuited its iron core will be?
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.
secondary
current
transformer
open-circuited
iron
core
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101
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1
answer
asked
Mar 19, 2018
by
anonymous
The secondary of a current transformer is always short-circuited under operating conditions because it?
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.
secondary
current
transformer
short-circuited
operating
conditions
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74
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1
answer
asked
Mar 27, 2018
by
anonymous
The no-load current drawn by transformer is usually what per cent of the full-load current ?
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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156
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2
answers
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.
transformer
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83
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1
answer
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.
transformer
turns
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114
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1
answer
asked
Mar 19, 2018
by
anonymous
In a transformer routine efficiency depends upon?
Last answer:
In a transformer, routine efficiency depends upon load current and power factor of load.
transformer
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90
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1
answer
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.
transformer
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285
views
1
answer
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.
transformer
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1
answer
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.
transformer
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67
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1
answer
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.
transformer
conservator
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104
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3
answers
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.
transformer
harmonics
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69
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1
answer
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.
transformer
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105
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1
answer
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.
transformer
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70
views
1
answer
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.
transformer
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129
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1
answer
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.
function
breather
transformer
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108
views
1
answer
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.
power
distribution
transformer
turns
heavily
insulated
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70
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1
answer
asked
Mar 19, 2018
by
anonymous
In a transformer the resistance between its primary and secondary should be?
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.
transformer
resistance
between
primary
secondary
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101
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1
answer
asked
Mar 19, 2018
by
anonymous
If a transformer is continuously operated the maximum temperature rise will occur in?
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.
transformer
continuously
operated
maximum
temperature
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56
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1
answer
asked
Mar 19, 2018
by
anonymous
The hum in a transformer is mainly attributed to?
The hum in a transformer is mainly attributed to?
Last answer:
The hum in a transformer is mainly attributed to magnetostriction.
hum
transformer
mainly
attributed
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86
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1
answer
asked
Mar 19, 2018
by
anonymous
The path of magnetic flux in a transformer should have?
The path of magnetic flux in a transformer should have?
Last answer:
The path of magnetic flux in a transformer should have low reluctance.
magnetic
flux
transformer
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270
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1
answer
asked
Mar 19, 2018
by
anonymous
In the transformer which winding has got more cross-sectional area?
Last answer:
In the transformer low voltage winding has got more cross-sectional area.
transformer
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133
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1
answer
asked
Mar 19, 2018
by
anonymous
Transformer breaths in when?
Last answer:
Transformer breaths in when load on it decreases.
transformer
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65
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1
answer
asked
Mar 19, 2018
by
anonymous
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.
transformer
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87
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1
answer
asked
Mar 19, 2018
by
anonymous
The chemical used in breather for transformer should have the quality of?
Last answer:
The chemical used in breather for transformer should have the quality of cleansing the transformer oil.
transformer
breather
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94
views
1
answer
asked
Mar 19, 2018
by
anonymous
The transformer ratings are usually expressed in terms of?
Last answer:
The transformer ratings are usually expressed in terms of kVA.
transformer
rating
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210
views
1
answer
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 .
transformer
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49
views
1
answer
asked
Mar 19, 2018
by
anonymous
Which type of winding is used in 3 phase shell-type transformer ?
Last answer:
Sandwich type winding is used in 3 phase shell-type transformer.
type
winding
used
phase
shell-type
transformer
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108
views
1
answer
asked
Mar 19, 2018
by
anonymous
Reduction in core losses and increase in permeability are obtained with transformer employing?
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.
reduction
core
losses
increase
permeability
obtained
transformer
employing
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592
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1
answer
asked
Mar 19, 2018
by
anonymous
what do not change in transformer?
what do not change in transformer?
Last answer:
Frequency and power are constant in transformers. Suppose we apply 50 Hz input frequency then the output frequency will also be 50 Hz whether the transformer is step up or step down. Similar ... is decreased on secondary side and hence power on primary side and secondary side remains constant.
change
transformer
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77
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1
answer
asked
May 22, 2020
by
anonymous
State why a transformer always have an efficiency of more than 90%.
State why a transformer always have an efficiency of more than 90%.
Last answer:
As transformer is static device with no moving parts, the losses due to friction & windage are completely absent. Hence transformer has efficiency of more than 90%.
transformer
efficiency
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31
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1
answer
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
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.
transformer
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102
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1
answer
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.
transformer
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137
views
1
answer
asked
Mar 19, 2018
by
anonymous
Primary winding of a transformer?
Last answer:
Primary winding of a transformer could either be a low voltage or high voltage winding.
transformer
primary
winding
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62
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1
answer
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.
transformer
efficiency
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60
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1
answer
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.
transformer
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1
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