Answer / prmeghwanshi

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.

Answer / vasi

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

Answer / arvind

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.

Answer / san

its good question

You must start the engineering from first stage...


Very good

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