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Helical coils can be used on?
asked
Mar 19, 2018
by
anonymous
transformer
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answered
Mar 19, 2018
by
anonymous
Helical coils can be used on
low voltage side of high kVA transformers.
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asked
Mar 19, 2018
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anonymous
Spacers are provided between adjacent coils?
Last answer:
Spacers are provided between adjacent coils to provide free passage to the cooling oil.
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197
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1
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Mar 19, 2018
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Iron loss of a transformer can be measured by?
Last answer:
Iron loss of a transformer can be measured by low power factor wattmeter.
iron
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transformer
measured
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2
asked
Mar 19, 2018
by
anonymous
A transformer can have regulation closer to zero?
Last answer:
A transformer can have regulation closer to zero on leading power factor.
transformer
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zero
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86
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1
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3
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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103
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1
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4
asked
May 22, 2020
by
anonymous
Explain the effect of Harmonics on the Transformer.
Explain the effect of Harmonics on the Transformer.
Last answer:
Effect of Harmonics on the Transformer: 1. Core loss: Harmonic voltage increases the hysteresis and eddy current losses in the lamination. The amount of the core loss depends on ... small core vibrations. 5. Saturation problem: Sometimes additional harmonic voltage causes core saturation.
harmonics
transformer
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5
asked
May 10, 2020
by
anonymous
Transformer on DC
Write about transformer on DC.
Last answer:
Transformer on DC : Transformer cannot work on DC. Transformer works on electromagnetic induction principle. Electromagnetic induction principle means when flux linking with coil changes and EMF induced in it ... winding insulation will burn. https://youtu.be/TVp_0fIfxqY
transformer
on
dc
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6
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
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7
asked
Mar 19, 2018
by
anonymous
The size of a transformer core will depend on?
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.
size
transformer
core
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1
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8
asked
Mar 19, 2018
by
anonymous
An open-circuit test on a transformer is conducted primarily to measure?
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
open-circuit
test
transformer
conducted
primarily
measure
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254
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2
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9
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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10
asked
Mar 19, 2018
by
anonymous
If a transformer is switched on to a voltage more than the rated voltage?
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.
transformer
switched
voltage
rated
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70
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1
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11
asked
Mar 19, 2018
by
anonymous
Sumpner's test is conducted on transformer to determine?
Sumpner's test is conducted on transformer to determine?
Last answer:
Sumpner's test is conducted on transformer to determine temprature.
sumpners
test
conducted
transformer
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91
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1
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12
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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92
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1
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13
asked
Mar 19, 2018
by
anonymous
The chemical used in breather is?
Last answer:
The chemical used in breather is silica gel.
breather
transformer
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53
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1
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14
asked
Mar 19, 2018
by
anonymous
Material used for construction of transformer core is usually?
Last answer:
Material used for construction of transformer core is usually silicon steel.
transformer
core
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111
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1
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15
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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1
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16
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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17
asked
Mar 19, 2018
by
anonymous
Silicon steel used in laminations mainly reduces?
Last answer:
Silicon steel used in laminations mainly reduces hysteresis loss.
transformer
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171
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1
answer
18
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
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1
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19
asked
Mar 19, 2018
by
anonymous
A transformer oil must be free from?
Last answer:
A transformer oil must be free from moisture.
transformer
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43
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1
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20
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
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21
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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66
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1
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22
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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97
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1
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23
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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96
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1
answer
24
asked
Mar 19, 2018
by
anonymous
The dielectric strength of transformer oil is expected to be?
The dielectric strength of transformer oil is expected to be?
Last answer:
The dielectric strength of transformer oil is expected to be 33 kV.
dielectric
strength
transformer
oil
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113
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1
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25
asked
Mar 19, 2018
by
anonymous
A Buchholz relay can be installed on?
Last answer:
A Buchholz relay can be installed on oil cooled transformers.
relay
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51
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1
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26
asked
May 22, 2020
by
anonymous
List two special feature of welding transformer.
List two special feature of welding transformer.
Last answer:
Special features of welding transformer: i) It is a step down transformer that reduces the source voltage to a voltage desired according to the demands of the welding process. ii) Having large primary turns and less ... V ii) Secondary voltage - 40 to 60 V iii) Secondary current - 200 to 600 A
special
feature
welding
transformer
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35
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1
answer
27
asked
May 22, 2020
by
anonymous
State two applications of isolation transformer
State two applications of isolation transformer
Last answer:
Applications of isolation transformer: i) Isolates the load equipment from supply ground: ii) Reduction of voltage spikes iii) It acts as a decoupling device. iv) Protects loads from harmonic distortion.
applications
isolation
transformer
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25
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1
answer
28
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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29
asked
May 17, 2020
by
anonymous
Equivalent circuit of transformer
Equivalent circuit of transformer
Last answer:
Equivalent Circuit Diagram of Transformer Referred to Primary: V1 -Primary Input voltage I1 - Input Current I0- Exciting current/ No load current Im- Magnetizing component ... equivalent of secondary terminal voltage ZL- Load impedance ZL ′- Primary equivalent of load impedance
equivalent
circuit
transformer
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224
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2
answers
30
asked
May 16, 2020
by
anonymous
Single phase transformer
Single phase transformer
Last answer:
Single phase Transformer Transformer
single
phase
transformer
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234
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1
answer
31
asked
May 15, 2020
by
anonymous
What is the use of transformer?
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.
use
transformer
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138
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1
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32
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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71
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0
answers
33
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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99
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1
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34
asked
Jul 27, 2019
by
anonymous
State any four characteristics of core type transformer.
State any four characteristics of core type transformer.
Last answer:
Characteristics of core type transformer: i) It has one window. ii) It has one magnetic circuit. iii) Core surrounds the winding. iv) Average length of core is more. v) Area of cross ... Better cooling for winding. vii) Mechnical strength is comparatively less. viii) Repair and maintenance is easy.
core
type
transformer
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69
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1
answer
35
asked
Jul 26, 2019
by
anonymous
Explain construction and working of single phase Auto transformer.
Explain construction and working of single phase Auto transformer.
Last answer:
Construction of single phase auto transformer: (i) It has only one winding wound on a laminated circular magnetic core. (ii) The core is made of silicon steel stampings. (iii) The two terminals of the ... help of handle. 5) The same transformer can be used as step-up or step down auto-transformer
transformer
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107
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1
answer
36
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°.
transformer
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60
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1
answer
37
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
38
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
39
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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132
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1
answer
40
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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61
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1
answer
41
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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105
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1
answer
42
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
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43
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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77
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1
answer
44
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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89
views
1
answer
45
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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56
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1
answer
46
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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64
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1
answer
47
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
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48
asked
Mar 19, 2018
by
anonymous
Greater the secondary leakage flux?
Last answer:
Greater the secondary leakage flux less will be the secondary induced e.m.f.
transformer
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115
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1
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49
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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272
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1
answer
50
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