Electrical Engineering - What is the power ratio between power in Star and Delta circuit?

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What is the power ratio between power in Star and Delta circuit?

Total Answers and Comments: 13

Last Update: October 06, 2009 Asked by: v.sudhir

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Best Rated Answer

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Submitted by: KaranSorout

The power ratio between Star to Delta is 1:3

Explanation:

Let’s suppose V_sbe the supply voltage per phase.

So the line voltage of the supply will be Ö3V_s.

Now assume any type of load; for simplicity I’m assuming it a only resistive load.

And let it be ‘R’ per phase.

For Delta connected load:

Calculation for per phase power; P_D= I²R

Where I à load current (per phase)

And,

I = Ö3V_s/R {as line voltage of the supply is directly applied to the phase of the delta load}

So,

P_d= (Ö3V_s/R)²R = 3V_s²/Rwatts per phase.

For 3 phases:

P_3D= 3P_d = 3*3V_s²/R = 9V_s²/R watts.

Now for Star connected load:

P_S= I²R = (V_s/R)²R = V_s²/R watts

For 3 phases: P_3S= 3P_S= 3 V_s²/R watts

Conclusion:

P_3S/ P_{3D =}3V_s²/R / 9V_s²/R = 1/3

It may be better concluded by drowing figures. If any variations, can connect to me through karan.sorout@gmail.com

Above answer was rated as good by the following members:
rahulr30, Ei Ei Thet, bragadeeshwaran, GeeK_Percy

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July 06, 2006 08:24:13

SASI KUMAR.A

RE: What is the power ratio between power in Star

The Power Ratio between STAR and DELTA is 1:3

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July 13, 2006 01:05:43

KaranSorout

Member Since: July 2006 Contribution: 4

RE: What is the power ratio between power in Star

The power ratio between Star to Delta is 1:3

Explanation:

Let s suppose V_sbe the supply voltage per phase.

So the line voltage of the supply will be 3V_s.

Now assume any type of load; for simplicity I m assuming it a only resistive load.

And let it be R per phase.

For Delta connected load:

Calculation for per phase power; P_D I²R

Where I load current (per phase)

And

I 3V_s/R {as line voltage of the supply is directly applied to the phase of the delta load}

P_d ( 3V_s/R)²R 3V_s²/Rwatts per phase.

For 3 phases:

P_3D 3P_d 3*3V_s²/R 9V_s²/R watts.

Now for Star connected load:

P_S I²R (V_s/R)²R V_s²/R watts

For 3 phases: P_3S 3P_S 3 V_s²/R watts

Conclusion:

P_3S/ P_3D3V_s²/R / 9V_s²/R 1/3

It may be better concluded by drowing figures. If any variations can connect to me through karan.sorout@gmail.com

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July 17, 2006 03:08:43

akhileshkesavanunnithan

Member Since: July 2006 Contribution: 2

RE: What is the power ratio between power in Star

the answer is 1/3

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July 31, 2006 23:49:54

sibani

RE: What is the power ratio between power in Star

1:2

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February 25, 2007 01:55:47

sonu14g2003

Member Since: February 2007 Contribution: 2

RE: What is the power ratio between power in Star

its actually 1:3 and the explaination is given above

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April 11, 2008 15:51:35

andyarok

Member Since: April 2008 Contribution: 2

RE: What is the power ratio between power in Star and Delta circuit?

Wow guys what happened? Never give wrong info guys. Total Power remains the same.

Irrespective of the type of connection Power remains same. Imagine that u loose 1/3 of the power for every Y-delta T.F. Dont Joke pa.

If u need explanation then will reply

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April 22, 2008 06:50:26

kanchan13

Member Since: April 2008 Contribution: 2

RE: What is the power ratio between power in Star and Delta circuit?

power is same

its only the line currents and voltages which differ in star and delta circuits.

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May 06, 2008 05:48:24

vishwas_deshmukh

Member Since: May 2008 Contribution: 4

RE: what is olc and how it will work in transmission system?

it is type of communication in which we use differete frequencies .communiacte via same conductor which is use for transmission .

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September 30, 2008 15:38:00

munish1983

Member Since: September 2008 Contribution: 5

RE: What is the power ratio between power in Star and Delta circuit?

Power is same in both star and delta connections which is √3 VL.ILcosΦ. So power ratio is 1:1

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February 17, 2009 01:52:48

#10

scientist007

Member Since: February 2009 Contribution: 2

RE: What is the power ratio between power in Star and Delta circuit?

Whatever be the connection whether it is delta or star total power remains same. So their will be 1:1
Thanks

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