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Question
```sigal phase supply is 230 v ac
two phase supply is 415 v ac
why three phase supply is 415 v ac why not 690 v ac```
Question Submitted By :: Srv.26@rediffmail.com
I also faced this Question!!     Rank Answer Posted By

Re: sigal phase supply is 230 v ac two phase supply is 415 v ac why three phase supply is 415 v ac why not 690 v ac
# 1
its good question

You must start the engineering from first stage...

Very good

 Is This Answer Correct ? 1 Yes 15 No
San

Re: sigal phase supply is 230 v ac two phase supply is 415 v ac why three phase supply is 415 v ac why not 690 v ac
# 2
Because you measure voltage between onlt two point like RYB
when you connect N to any other RYB then voltage is 240V
(App.) this is called single phase.
when you connect one point into RYB(R) and other is also RYB
(other than R) is 440V this two phash. when you use three
phase voltage is measure in only two point like R to B R to
Y so it is also 440V. you can't measure voltage betwween
three point.

 Is This Answer Correct ? 14 Yes 3 No
Prmeghwanshi
[Larsen & Toubro Limited]

Re: sigal phase supply is 230 v ac two phase supply is 415 v ac why three phase supply is 415 v ac why not 690 v ac
# 3
If Phase-Neutral voltage is 230v then Phase-Phase voltage in
3ph system willbe sq.root of 3 X 230v
The 3 ph are displaced 0-120-240 degrees and the Pitagor
Theorem can be used to count up the Line voltage
Another way to count up the Line(Phase-Phase) voltage is to
use vector analysis
1st Phase 0 degree 230+j0
2nd Phase 120 degrees cos120*(230) + sin120*(230) this gives
-115+j199
3rd Phase 240 degrees cos240*(230) + sin240*(230) this gives
-115-j199
in the end ph1-ph2 398v, ph1-ph3 398v, ph2-ph3 398v

 Is This Answer Correct ? 7 Yes 1 No
Vasi

Re: sigal phase supply is 230 v ac two phase supply is 415 v ac why three phase supply is 415 v ac why not 690 v ac
# 4
its a very good question, see what we r measuring is phase
to phase voltage, in case of 3phase system,that means
beetween two phase is simple because we have two points of
voltmeter to measure the voltage.

 Is This Answer Correct ? 1 Yes 4 No
Arvind

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