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What is an auto transformer starter?
asked
Mar 15, 2018
by
anonymous
What is an auto transformer starter?
auto
transformer
starter
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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
May 3, 2018
by
anonymous
Auto reclosing is used in case of
Auto reclosing is used in case of
Last answer:
Auto reclosing is used in case of air blast C.B.
auto
reclosing
used
case
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71
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1
answer
asked
Mar 20, 2018
by
anonymous
A three point starter is considered suitable for?
Last answer:
A three point starter is considered suitable for shunt as well as compound motors.
three
point
starter
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76
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1
answer
asked
Mar 20, 2018
by
anonymous
A direct online starter is used for starting motors?
Last answer:
A direct online starter is used for starting motors up to 5 H.P.
direct
online
starter
starting
motors
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59
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1
answer
asked
Mar 20, 2018
by
anonymous
For starting a D.C. motor a starter is required because?
Last answer:
For starting a D.C. motor a starter is required because it limits the starting current to a safe value.
starting
dc
motor
starter
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62
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1
answer
asked
Mar 20, 2018
by
anonymous
Three point starter can be used for?
Last answer:
Three point starter can be used for both shunt and compound motor.
three
point
starter
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64
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1
answer
asked
Mar 15, 2018
by
anonymous
Why starter is required for starting an induction motor?
Why starter is required for starting an induction motor?
starter
starting
induction
motor
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93
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0
answers
asked
Mar 10, 2018
by
anonymous
What is the best Arduino starter kit?
What is the best Arduino starter kit?
arduino
starter
kit
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60
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0
answers
asked
Nov 30, 2017
by
anonymous
what is the difference between four point starter and three point starter?
what is the difference between four point starter and three point starter?
Last answer:
The only difference is in the NO VOLT COIL connection in the starter, in three point starter NVC is connected to the field whereas in four point starter it is connected separately. The advantage of using ... (for above rated speed) and lead to DEENERGISE the NVC leading to turning off of the motor.
four
point
starter
three
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87
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1
answer
asked
Jun 29, 2019
by
anonymous
What is auto transformer
transformer
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59
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0
answers
asked
Mar 15, 2018
by
anonymous
Which type of starter is used to start the DC motor?
Which type of starter is used to start the DC motor?
type
starter
used
start
dc
motor
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0
answers
asked
May 22, 2020
by
anonymous
Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter.
Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter.
Last answer:
Necessity of Starter for D.C. Motor: Armature current is given by equation Ia = (V−Eb)/Ra i) If the motor is at standstill or rest, back emf Eb is zero (as Eb= ZNP/(60A), at start speed N ... . Types of D.C. motor starters: i) Two point starter ii)Three point starter iii) Four point starter
starter
dc
motor
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1
answer
asked
Jul 30, 2019
by
anonymous
Draw the wiring diagram of fluorescent tube. Explain the working of choke and starter.
Draw the wiring diagram of fluorescent tube. Explain the working of choke and starter.
Last answer:
Fluorescent lamp:- Operation:- When switch is ON current flows through the choke-filament no1- starter-filament no. 2- to neutral, At that time choke induces high voltage which is applied to ... at the time of starting. ii) Starter: To make and break the circuit to start the tube.
wiring
diagram
fluorescent
tube
choke
starter
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1
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asked
Sep 23, 2018
by
anonymous
State any four advantages of soft starter.
State any four advantages of soft starter.
Last answer:
Advantages of soft starter: 1. Very low line voltage drops on motor operation 2. Reduced energy losses in the lines 3. System efficiency increases 4. Very smooth starting & operation 5. As ... may lead to lower MD billing. 13. Less mechanical maintenance. 14. Saving in operating costs.
advantages
soft
starter
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106
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1
answer
asked
Sep 18, 2018
by
anonymous
State function of starter and ELCB. (Earth Leakage Circuit Breaker)
State function of starter and ELCB. (Earth Leakage Circuit Breaker)
Last answer:
i) Function of Starter:- 1. To prevent the high starting current OR to minimize the starting current. 2. To give supply failure protection 3. To give over load and short circuit protection ... an installation and cut off the circuit from power supply and avoid electrical shock to the person.
function
starter
elcb
earth
leakage
circuit
breaker
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1
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asked
Mar 20, 2018
by
anonymous
In a manual shunt motor starter?
Last answer:
In a manual shunt motor starter over load relay is connected in series and no volt relay in parallel with the load.
manual
shunt
motor
starter
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46
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1
answer
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
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
May 1, 2018
by
anonymous
The desirable properties of transformer core material are
The desirable properties of transformer core material are (1) low permeability and low hysteresis loss. (2) high permeability and high hysteresis loss. (3) high permeability and low hysteresis loss. (4) low permeability and hysteresis loss.
Last answer:
The desirable properties of transformer core material are high permeability and low hysteresis loss.
desirable
properties
transformer
core
material
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125
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1
answer
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
An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to secondary turn’s ratio 12:1. The peak inverse voltage is A) 8.62 V B) 12 V C) 19.17 V D) 27.11 V
Last answer:
An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to secondary turn’s ratio 12:1. The peak inverse voltage is A) 8.62 V B) 12 V C) 19.17 V D) 27.11 V
ac
supply
half-wave
rectifier
circuit
transformer
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120
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1
answer
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
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.
transformer
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134
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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.
transformer
ideal
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68
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1
answer
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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268
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2
answers
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
Mar 21, 2018
by
anonymous
The stator of phase shifting transformer for use in conjunction with an A.C. potentiometer usually has a?
Last answer:
The stator of phase shifting transformer for use in conjunction with an A.C. potentiometer usually has a two-phase winding.
stator
phase
shifting
transformer
use
conjunction
ac
potentiometer
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120
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1
answer
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
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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76
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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 14, 2018
by
anonymous
Why does a transformer only work with an AC supply?
Why does a transformer only work with an AC supply?
Last answer:
The transformer work depends on the induction as main principle ,for that AC is the right means
transformer
only
work
ac
supply
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109
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3
answers
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
answer
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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118
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1
answer
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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74
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1
answer
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
answer
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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56
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0
answers
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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123
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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
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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134
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1
answer
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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485
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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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76
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1
answer
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
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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101
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1
answer
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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1.5k
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1
answer
asked
May 20, 2018
by
anonymous
A 400V/100 V, 10 KVA two-winding transformer is reconnected as an auto-transformer across a suitable
A 400V/100 V, 10 KVA two-winding transformer is reconnected as an auto-transformer across a suitable voltage source. The maximum rating of such an arrangement could be A) 50 KVA B) 15 KVA C) 12.5 KVA D) 8.75 KVA
Last answer:
A 400V/100 V, 10 KVA two-winding transformer is reconnected as an auto-transformer across a suitable voltage source. The maximum rating of such an arrangement could be 50 KVA
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78
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1
answer
asked
May 25, 2018
by
anonymous
An auto transformer having a transformation ratio of 0.8 supplies a load of 10 kW. The power transferred
An auto transformer having a transformation ratio of 0.8 supplies a load of 10 kW. The power transferred inductively from the primary to secondary is (a) 2 kW (b) 4 kW (c) 8 kW (d) 10 kW
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283
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0
answers
asked
May 8, 2018
by
anonymous
An Auto-transformer (which has only one winding) may be used as a ______ .
An Auto-transformer (which has only one winding) may be used as a ______ . (A) Both Step-Up and Step-Down transformer (B) Step-Down Transformer (C) Step-Up Transformer (D) None of these
Last answer:
an autotransformer may used only as step down transformer
auto-transformer
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4.9k
views
2
answers
asked
Aug 22, 2019
by
Iqrima
Transformer is 180 degree phase shifting device.pls explain
transformer
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101
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0
answers
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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1
answer
asked
Aug 12, 2018
by
anonymous
Why Transformer rating is given in kVA?
Why Transformer rating is given in kVA?
Last answer:
1) The output of transformer is limited by heating due to the losses. Two types of losses in the transformer (i) Iron loss, (ii) Copper loss. 2) Iron loss depends on the transformer voltage (V). ... by load power factor. - Hence the transformer output is expressed in VA or kVA and not in kW.
transformer
rating
kva
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4
answers
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