Why are we employing star type transformer at transmission end and delta type transformer at receiving end?

UMESH KUSHWAHA

• May 23rd, 2012

Its not necessary to use only Delta type T/F at receiving end, we can also used star type but in this case at same voltage level two star neutral point create due to which Harmonic create for avoiding this we prefer opposite combination at sending end and receiving end.

vishal badlas

 Profile Answers by vishal badlas Questions by vishal badlas

• May 19th, 2012

Bcoz at the transmission side especially for secondary distribution we need neutral wire for getting single phase supply and star type is only one which provide neutral. at receiving side to step up voltage we need delta type connection.

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anass mugdam

• Apr 29th, 2018

The frequency of a system is dependent on the active power balance. As frequency is a common factor throughout the system, a change in active power demand at one point is reflected throughout the sys...

Rockhy

• Dec 2nd, 2011

Frequency means Cycles Per Second ...So to Maintain Phase Difference of 120 degree between three phase to achieve Perfect Sine Wave Frequency Should Remain Constant ..if we dont Maintain the Constant Frequency then there will Be Fluctuation in Voltage as Voltage Is Directly proportional to frequecy

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SONI RANJAN MAHAPATRA

• Apr 23rd, 2013

As we know the main function of transformer is to transfer power from one ckt to another ..so ratio will same on both side of transformer..it only change the ratio of voltage and current .

praveen kumar

• Mar 8th, 2013

Power is same, so the ratio is 1:1

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atul sudhakar

• May 2nd, 2014

In simple words, the power which is used to setup a magnetic field for the machine

jagadish

• Sep 21st, 2013

Reactive power is the virtual oscillating power in the power system that enables active power to do the work in the system.So it is necessary for the power system.

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roshan kumar jha

• Sep 24th, 2014

Coz of form factor generally

kumar sundram

• Sep 19th, 2014

If you notice that 765,1200,400kv is always assumption based questions not in reality.But any practical point of view it is always multiple of 11 because of form factor dear.

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An overexcited alternator gives current at which power factor?Why?

Tuleswar Patel

• Apr 15th, 2015

As it is driving current i.e graeater than the rated value the pf will be leading .

satyam

• Mar 21st, 2015

It will operate in leading power factor, it is also called synchronous condenser.

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saginala13

 Profile Answers by saginala13 Questions by saginala13

• Jun 19th, 2010

Synchronous motor: we will give dc supply to the armature as a excitation, which causes revolving flux, so that motor will rotate at synchronous speed.if there is no excitation and the armature coils ...

GeeK_Percy

 Profile Answers by GeeK_Percy Questions by GeeK_Percy

• Oct 4th, 2009

Armature winding is 3 phase winding and is supplied with 3 phase supplyField is supplied with DC supplied First motor is run at syn speed to lock rotor in syn speed now load is applied Questioner is confused actually the rotating field is produced by armature not by field.

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If v=220V, I=25A, power factor=0.8, frequency=400Hz. If the motor runs for 3 hours, What is the power consumed?

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 10th, 2011

Calculating power, frequency and time is not required. P=V*I*Cos0 =220*25*0.8 =4400 watts answer But if you are looking for "How much energy motor consumed?" then you need time Energy consumed ...

dineshkumarsah.mj

 Profile Answers by dineshkumarsah.mj Questions by dineshkumarsah.mj

• Jun 15th, 2011

Here Freq was given was wrong P V*I*CosAA is power factor V is VoltageI is Current P 220*25*0.8P 4400wattsPower P is 4.4Kwatts for one hour.For 3 hrs 4.4KW*3 = 13.2KW

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Srinath

• Oct 6th, 2016

Can you elaborate the reason why we have cos angle for active power and sine angle for reactive power?

ABC

• Sep 4th, 2011

Bcz in impedence triangle(cos=b/h) R(resistance) is in the base and imepedence is hypotaneous.
power factor(cos )=R/Z. THATS WY WE are using cos in the power factor notation.

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shashi kant

• Jul 19th, 2011

when we increase the load current increases because when load is increased power consumption increases and p=sq.root3.V.I.cos q. according to the expression, voltage & p.f. remains the same for a part...

saginala13

 Profile Answers by saginala13 Questions by saginala13

• Jun 19th, 2010

Increase in load means, we are utilising more power , and the voltage of many systes is almost constant. so for increasing power current will increase.

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Shona Balaji Santharam

• Jan 1st, 2018

Knee Point Voltage of Current Transformer is the significance of saturation level of a CT core mainly used for protection purposes. The sinusoidal voltage of rated frequency applied to the secondary t...

ravikaurase

 Profile Answers by ravikaurase Questions by ravikaurase

• Nov 10th, 2010

To know Whether the CT is saturated or not.

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gagan.bhatia

 Profile Answers by gagan.bhatia Questions by gagan.bhatia

• Oct 25th, 2016

In electrical engineering, a synchronous condenser (sometimes called a synchronous capacitor or synchronous compensator) is a device identical to a synchronous motor, whose shaft is not connected to anything but spins freely.

romeo vincent

• Oct 18th, 2016

What is the advantage of capacitor used in ballast for discharge lamp?

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Shivam Jha

• Oct 16th, 2013

Regulator is a device used to vary the supply voltage according to our use.Where as stabilizer is a static device which is used to maintain constant supply voltage

abhisek kundu

• Sep 18th, 2013

Regualtor is for d.c application & stabilizer is for a.c application

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Why Cable selection depends on Load current? (UG Cables & OH lines)

soumendasbiswas

 Profile Answers by soumendasbiswas Questions by soumendasbiswas

• Apr 26th, 2012

Cable selection not only depends on the load current but also depends on Temperature, Length (Distance between LT Switchgear MCC/PMCC to Motor). If load is increase then current will also increase if ...

raju

• Apr 6th, 2012

Voltage is directly proportional length, current is proportional to area of cross section of the wire.

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What is the distance between R, Y and B wires when the line is going from one sub-station to another sub-station?

SAUNAK NANDY

• Aug 31st, 2011

The distance between R,Y and B wire should be of 120 degree phase difference.

gowtham

• Aug 26th, 2011

55cm

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How we can step-up or step-down the DC voltage directly?

S.Ghosh

• May 23rd, 2012

A chopper is nothing but a thyristor/SCR/transistor circuit which operates with the principle of PWM (Pulse Width Modulation). If you need to boost DC voltage with chopper, additional circuits includi...

sai charan

• May 20th, 2012

this can be done by using chopper.chopper is a dc equivalent of a.c transformer to which d.c input which is to be stepped up is applied at input terminals and output is taken from output terminals whi...

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Which of the following test are to be conducted for the determination of voltage regulation of a transformer.a. Load Testb. Short Circuit Testc. OC Testd. Retardation Test.

SUBHABRATA BASAK

• Oct 9th, 2017

B. Short Circuit Test

SUBHABRATA BASAK

• Oct 9th, 2017

SC Test Only... But also need to know about PF of the Load as V.R. of transformer depends on PF of Load

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If the capacity of a Transformer is 20/26 then what does 20/26 shows? what is its purpose?

pveee

 Profile Answers by pveee Questions by pveee

• Dec 29th, 2011

If 20/26 is in kva 20kva indicates capacity of transformer under ONAN cooling.

If the capacity is 26kva it is provided with ONAF cooling.

If 20/26 is voltage 20 indicate primary side voltage, 26 indicates secondary voltage, it is stepup transformer.

narasaiah

 Profile Answers by narasaiah Questions by narasaiah

• Nov 7th, 2009

20/26 means 20 primary voltage rating 26 secondary voltage rating

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If Heater of 1000W is connected in series with 60 W bulb. what is the effect on the bulb.

SURAJTHEGREAT

 Profile Answers by SURAJTHEGREAT Questions by SURAJTHEGREAT

• May 5th, 2012

1 Thing everybody has to remember is that only current and not the voltage remains constant across the elements.Let us assume that the elements in series are connected to 220V supply source. Total po...

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 9th, 2011

@ om_zzz

You are right, bulb will glow but dimmer and heater will not heat-up(more precisely it will generate very less heat)

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Why the reactive componet is generated in power system?

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 10th, 2011

If alternator is Overexcited, it will deliver reactive power with lagging current while in Underexcited, it absorb reactive power with leading curreent But, it always(under or over-excited) deliver ...

Sagar_upadhyay

• Sep 25th, 2011

In most of the power stations, the generation takes place by synchronous generators. The synchronous generators are doubly excited in nature. When the rotor is fed with a DC field, power is generated....

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