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Anonymous Poster #1

2 Phase Power

03/14/2013 2:19 PM

2 active resistors each 10 Ohm. Phase voltage 220V, line voltage 380V.

220V Phase A --- R 10 Ohm ---Neutral ----R 10 Ohm ---220V Phase B

P = 2(220V*22A) = 9680W ?

or

P = 1.41*380V*22A = 11787W ?

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Guru
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#1

Re: 2 Phase Power

03/14/2013 5:45 PM

P = 2(220V*22A) = 9680W

Question for you. What is the amperage on the neutral?

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Anonymous Poster #1
#2
In reply to #1

Re: 2 Phase Power

03/15/2013 1:36 AM

Thanks for your answer, Waregle. Current should be both neither 22A nor 44A (if there were 3 phases and 3 equal loads then curr = 0). I always have had difficulties with these phasor calculations.

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Guru
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#3
In reply to #1

Re: 2 Phase Power

03/16/2013 6:12 AM

In=(1/√(Ia²+Ib²))*100

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Anonymous Poster #1
#4
In reply to #1

Re: 2 Phase Power

03/16/2013 11:20 AM

Ampers in the neutral should be about 31A.

Then ,

P = 1.41*220*31?

I always thought we multiply the square root of 2 with line voltage and phase amperage (just like the sq root of 3 for 3 phase load) - now it seems we should multiply it with phase voltage and neutral amperage?

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Guru
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#5

Re: 2 Phase Power

03/16/2013 1:25 PM

Since these currrents are 120 degrees apart, the neutral current must be added using vectors.

In = Ia @0 degrees + Ib @ 120 degrees.

In = 22 +J0 + (-22 cos 120 + 22 sin 120)

In =22 + 0 - 22 x .50 + 22 x 0.866 = 22 amps at 60 degrees.

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Guru
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#6

Re: 2 Phase Power

03/16/2013 5:45 PM

Are we talking about phases at 120° or 90°

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Anonymous Poster #1
#7

Re: 2 Phase Power

03/17/2013 3:42 AM

Did not know it is so complicated. Thank you for answers. But, in any way, IS the power consumed 9680 W ?

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Guru
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#8

Re: 2 Phase Power

03/17/2013 6:53 PM

The voltage give appear to be a wye connection.

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Power-User

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#9
In reply to #8

Re: 2 Phase Power

03/18/2013 1:21 PM

Wye with neutral - 2 shoulders of which have each a resistor 10 Ohm. Phase to phase 380 V, phase to neutral 220 V.

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