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what is transformer ?
asked
Aug 6, 2017
by
anonymous
what is transformer ?
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1
Answer
answered
Sep 2, 2017
by
Nilakantha Bihari
Transformer is a device which is used to convert AC electricity from one voltage to another voltage without any change in frequency .
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asked
Aug 27, 2019
by
anonymous
What is the back E.M.F in Transformer ?
What is the back E.M.F in Transformer ?
Last answer:
Back emf in transformer is when apply voltage in primary side of transformer. This voltage produce flux according to Faraday law electro magnetic induction. This flux called mutual flux and this ... secondary flux oppos the applied voltage according to lenz law. its called back emf of transformer
transformer
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1
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asked
Jul 24, 2019
by
Deepak kumar bharti
What is largest rating transformer
transformers
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asked
Jun 29, 2019
by
anonymous
What is auto transformer
transformer
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asked
Sep 18, 2018
by
anonymous
What is an isolation transformer? State any two applications of isolation transformer.
What is an isolation transformer? State any two applications of isolation transformer.
Last answer:
i) Isolation transformers are specially designed transformers for providing electrical isolation between primary & secondary windings. The transformer has primary and secondary windings placed on the common core ... ground: ii) Reduction of voltage spikes iii) It acts as a decoupling device.
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1
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asked
Sep 15, 2018
by
anonymous
State what is the significance of conducting phasing out test on a 3-phase transformer? Explain its procedure with a suitable connection diagram.
State what is the significance of conducting phasing out test on a 3-phase transformer? Explain its procedure with a suitable connection diagram.
Last answer:
-Short primary & secondary winding of other phases expect the one under test. -Connect voltmeter to secondary winding. -A small DC current is circulated through the primary winding through ... . -The test repeated for finding out remaining concerned secondary windings in the same manner.
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2
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asked
May 13, 2018
by
anonymous
What should be kVA rating of each transformer in V-V bank when three phase balanced load is
What should be kVA rating of each transformer in V-V bank when three phase balanced load is 40 kVA ? (A) 19 (B) 28 (C) 37 (D) 23
Last answer:
What should be kVA rating of each transformer in V-V bank when three phase balanced load is 40 kVA ? (A) 19 (B) 28 (C) 37 (D) 23
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1
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asked
May 8, 2018
by
anonymous
What will happen if the primary of a transformer is connected to D.C. supply?
What will happen if the primary of a transformer is connected to D.C. supply? (A) Transformer will operate with low efficiency (B) Transformer will operate with high efficiency (C) No effect (D) Transformer may start to smoke and burn
Last answer:
What will happen if the primary of a transformer is connected to D.C. supply? (A) Transformer will operate with low efficiency (B) Transformer will operate with high efficiency (C) No effect (D) Transformer may start to smoke and burn
transformer
dc
supply
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1
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asked
Apr 29, 2018
by
anonymous
What is a capacitor voltage transformer?
What is a capacitor voltage transformer? A) It is a transformer used in power systems to step up low voltage signals and provide extra high voltage B) It is a transformer used in power systems to step up high voltage signals and provide extra high voltage C) It is a transformer used in power systems to step down extra high voltage signals and provide low voltage D) None of these
Last answer:
What is a capacitor voltage transformer? A) It is a transformer used in power systems to step up low voltage signals and provide extra high voltage B) It is a transformer used in power systems ... power systems to step down extra high voltage signals and provide low voltage D) None of these
capacitor
voltage
transformer
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75
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1
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asked
Apr 11, 2018
by
anonymous
What is the moving part of a linear variable differential transformer?
What is the moving part of a linear variable differential transformer? a) Primary c) Secondary b) Diaphragm d) Core
Last answer:
What is the moving part of a linear variable differential transformer? Core
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153
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1
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asked
Apr 5, 2018
by
anonymous
What is the basic principle of operation of a transformer?
What is the basic principle of operation of a transformer? (A) Self-induction (B) Mutual-induction (C) Static-induction (D) Dynamic-induction
Last answer:
B. Transformer works on principle of MUTUAL INDUCTION. When voltage is applied to the primary winding of the transformer, current flows through the current called magnetising current results in ... . Thus power flow from primary to secondary circuit is simply based on the mutual induction.
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asked
Mar 31, 2018
by
anonymous
What is the efficiency of transformer compared with that of electrical motors of the same power?
Last answer:
Much higher efficiency of transformer compared with that of electrical motors of the same power.
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asked
Sep 3, 2017
by
anonymous
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.
short
circuit
test
transformer
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asked
Sep 1, 2018
by
anonymous
What will be the efficiency when the transformer operates at unity power factor and 60% of full load
What will be the efficiency when the transformer operates at unity power factor and 60% of full load
Last answer:
What will be the efficiency when the transformer operates at unity power factor and 60% of full load 96.5%
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1
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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
power
transformer
designed
operation
frequency
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1
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asked
Oct 5, 2017
by
anonymous
what are the causes of noise in transformer?
Last answer:
Transformer noise is generated due to vibration of core and winding this is because of magnetostriction and magnetomotive force.
transformer
noise
causes
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1
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asked
Aug 15, 2017
by
anonymous
what are the uses of current transformer ?
what are the uses of current transformer ?
Last answer:
Uses of current transformer are as follows :A current transformer is use to measure Alternating current.A current transformer is used in meters.A current transformer is used in ammeters. ... .Current transformer is use with circuit breaker.Current transformer is use for overcurrent fault protection.
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1
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asked
Aug 6, 2017
by
anonymous
what are the types of transformer ?
what are the types of transformer ?
Last answer:
Power transformer, instrument transformer, pulse transformer, RF transformer, IF transformer, audio transformer, distribution transformer etc. are the types of transformer.
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179
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1
answer
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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1
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asked
Apr 16, 2020
by
bos
What is the efficiency of this transformer on full and half load.
1.) A 500kVA transformer has a primary winding resistance of 0.85Ω and a secondary winding resistance of 0.0025Ω. The primary and secondary voltages are 4.5kV and 600V, respectively. The iron loss is 6kW. If the power factor of the load is 0.75, determine the efficiency of the transformer on full load, and on half load.
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answers
asked
Jun 28, 2019
by
anonymous
What is the colour of silica gel in transformer?
Options: A) Yellow B) No colour C) White D) Blue
Last answer:
Correct Answer: D) Blue
silica
gel
colour
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asked
Oct 1, 2018
by
LAKKU ASHOK REDDY
What is the theory for load test on a single phase transformer?
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87
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0
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asked
Apr 23, 2018
by
anonymous
What is the line current of a circuit when the current transformer of 1000 : 5 rating measures 4 amp?
What is the line current of a circuit when the current transformer of 1000 : 5 rating measures 4 amp? (A) 5000 amp (B) 1000 amp (C) 400 amp (D) 800 amp
Last answer:
What is the line current of a circuit when the current transformer of 1000 : 5 rating measures 4 amp? (A) 5000 amp (B) 1000 amp (C) 400 amp (D) 800 amp
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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 ?
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
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asked
Mar 15, 2018
by
anonymous
What is an auto transformer starter?
What is an auto transformer starter?
auto
transformer
starter
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48
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0
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asked
Mar 10, 2018
by
anonymous
What is impulse voltage of transformer?
What is impulse voltage of transformer?
impulse
voltage
transformer
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asked
Dec 22, 2017
by
anonymous
What is the EMF equation of the transformer?
What is the EMF equation of the transformer?
Last answer:
E1 =2(3.142)fN1 (flux)1E2 =2(3.142)fN2(flux)2
emf
equation
transformer
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1
answer
asked
Dec 17, 2017
by
anonymous
What is the use of Buchholz relay in transformer?
What is the use of Buchholz relay in transformer?
Last answer:
This is a transformer that is used to step up and down current.
use
buchholz
relay
transformer
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115
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1
answer
asked
Aug 19, 2017
by
anonymous
what is mean by rotating transformer ?
what is mean by rotating transformer ?
Last answer:
Induction motor is a rotating transformer
rotating
transformer
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76
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1
answer
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 ?
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
protect
power
transformer
neutral
grounded
fault
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317
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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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1
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asked
Feb 17, 2018
by
anonymous
What are the design constraints of transformer design?
What are the design constraints of transformer design?
Last answer:
Design constraints of transformer design: Core loss, flux density, copper loss and total power loss vs flux density these are the basic constraints in transformer design. Core loss: Flux density: Copper loss: Total power loss vs flux density:
design
constraints
transformer
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88
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1
answer
asked
Mar 30, 2020
by
anonymous
Induced emf in the primary of transformer is equal to terminal voltage applied at primary
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0
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asked
Aug 22, 2019
by
Iqrima
Transformer is 180 degree phase shifting device.pls explain
transformer
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asked
Aug 13, 2019
by
Alacrity
the volt per turn of a certain single phase transformers is 1.7. the transformer has a step ratio of 3825/255volt. calculate the respective number of turns in each winding
single
phase
transformers
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asked
Oct 15, 2018
by
anonymous
In Scott connection transformer the turns ratio of main winding and teaser winding is ?
Last answer:
Turns ratio= N1/ N2 IN Scott connection Main transformer turns ratio = N1 /N2 Teaser transformer turns ratio= 0.866N1/N2 Where N1= number of turns in primary winding N2= number of turns in secondary winding
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1
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asked
Sep 18, 2018
by
anonymous
Give the criteria for selection of distribution transformer as per IS:10028 (part-I) 1985.
Give the criteria for selection of distribution transformer as per IS:10028 (part-I) 1985.
Last answer:
Criteria for selection of distribution transformer as per IS:10028 (part-I) 1985: 1) Total connected load. 2) Load Diversity factor. 3) Expected daily load curve. 4) Type of loads: ( ... or trends or forecasting. 10) Ambient conditions for deciding insulation class. 11) Tap changing requirement.
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asked
Sep 18, 2018
by
anonymous
Give the specification of three phase transformer as per IS 1180(Part-1) 1989.
Give the specification of three phase transformer as per IS 1180(Part-1) 1989.
Last answer:
Specification of 3-phase transformer: 1) kVA rating of transformer 2) Voltage ratings for the primary and secondary voltages 3) HV and LV currents 4) Operating frequency of the transformer 5) % impedance of ... the manufacturer 16) Weight of core 17) Weight of winding 18) Volume of oil in litres.
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1
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asked
Sep 2, 2018
by
anonymous
Write any four points that state how a traction transformer is different from ordinary transformer.
Write any four points that state how a traction transformer is different from ordinary transformer.
Last answer:
Ans: 1) Specially designed to withstand severe operating conditions. 2) Are required to have high short time peak capacity. 3) Class A insulation , specially reinforced to withstand frequent short circuits. 4) Can ... effect of SC impedance not less than 8.5 % for 10 MVA and 10 % for 12.5 MVA.
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asked
Sep 1, 2018
by
anonymous
A single phase 230 V/ 150 V , 1 kVA, 50 Hz transformer is supplied by 230 V AC supply. Find the full load primary and secondary current.
A single phase 230 V/ 150 V , 1 kVA, 50 Hz transformer is supplied by 230 V AC supply. Find the full load primary and secondary current.
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0
answers
asked
Sep 1, 2018
by
anonymous
KVA of an Auto-transformer of V1/V2 = 220/150 for a load of 100KVA is:
KVA of an Auto-transformer of V1/V2 = 220/150 for a load of 100KVA is: a. 100KVA b. 50KVA c. 33.3KVA d. 20KVA
Last answer:
KVA of an Auto-transformer of V1/V2 = 220/150 for a load of 100KVA is: a. 100KVA b. 50KVA c. 33.3KVA d. 20KVA
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1
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asked
May 13, 2018
by
anonymous
A d.c. voltage of 230 V is imposed on an unloaded 230 V, 50 Hz transformer, it will
A d.c. voltage of 230 V is imposed on an unloaded 230 V, 50 Hz transformer, it will (A) give high secondary voltage (B) burn out (C) give secondary voltage as per k (D) None of these
Last answer:
A d.c. voltage of 230 V is imposed on an unloaded 230 V, 50 Hz transformer, it will burn out
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60
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1
answer
asked
May 12, 2018
by
anonymous
The transformer which transforms unbalanced line to a balanced line is better known as
The transformer which transforms unbalanced line to a balanced line is better known as (A) Impedance transformer (B) Amplifier (C) Balun (D) Oscillator
Last answer:
The transformer which transforms unbalanced line to a balanced line is better known as Balun
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53
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1
answer
asked
Apr 30, 2018
by
anonymous
A transformer operates 24 hours day at full -load. It's full -load efficiency is :
A transformer operates 24 hours day at full -load. It's full -load efficiency is : (A) equal all day efficiency (B) more than all -day efficiency (C) less than all -day efficiency (D) equal to maximum efficiency
Last answer:
A transformer operates 24 hours day at full -load. It's full -load efficiency is : equal all day efficiency
transformer
operates
full
load
efficiency
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1
answer
asked
Apr 29, 2018
by
anonymous
Which of the following is true with an auto transformer?
Which of the following is true with an auto transformer? A) It has only one winding B) It has two separate windings namely primary winding and secondary winding C) It has two primary windings and one single secondary winding D) None of these
Last answer:
Which of the following is true with an auto transformer? A) It has only one winding B) It has two separate windings namely primary winding and secondary winding C) It has two primary windings and one single secondary winding D) None of these
auto
transformer
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67
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1
answer
asked
Apr 28, 2018
by
anonymous
When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is
When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is (A) 86.6% (B) 50% (C) 57.7% (D) 73.2%
Last answer:
When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is 73.2%
three
phase
system
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71
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1
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asked
Apr 28, 2018
by
anonymous
The main purpose of using core in a transformer is to
The main purpose of using core in a transformer is to (A) decrease iron losses (B) eliminate magnetic hysteresis (C) reduce reluctance of the common magnetic circuit (D) prevent eddy current loss
Last answer:
The main purpose of using core in a transformer is to reduce reluctance of the common magnetic circuit
transformer
core
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830
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1
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asked
Apr 25, 2018
by
anonymous
A 1100 kVA, 11 kV/1.1 kV conventional two-winding transformer is connected as a 12.1 kV/11 kV step-down ...
A 1100 kVA, 11 kV/1.1 kV conventional two-winding transformer is connected as a 12.1 kV/11 kV step-down auto-transformer. The rating of the auto-transformer is (A) 1000 kVA (B) 1100 kVA (C) 11000 kVA (D) 12100 kVA
Last answer:
A 1100 kVA, 11 kV/1.1 kV conventional two-winding transformer is connected as a 12.1 kV/11 kV step-down auto-transformer. The rating of the auto-transformer is 12100 kVA
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asked
Apr 25, 2018
by
anonymous
The main application of delta/zig-zag connected 3-phase transformer is to supply
The main application of delta/zig-zag connected 3-phase transformer is to supply (A) balanced loads (B) unbalanced loads (C) furnace loads (D) single-phase loads
Last answer:
The main application of delta/zig-zag connected 3-phase transformer is to supply unbalanced loads
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73
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1
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asked
Apr 25, 2018
by
anonymous
The power transformer is a
The power transformer is a (a) Constant current device (c) Constant power device (b) Constant voltage device (d) Pulsating main flux device
Last answer:
The power transformer is a Pulsating main flux device
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asked
Apr 12, 2018
by
anonymous
Transformer oil is used as ________.
Transformer oil is used as ________. A. Doping Element B. Coolant C. Power booster D. None
Last answer:
Transformer oil is used as Coolant.
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