3 Phase AC Supply

Why 440volts instead of 660volts in 3 phases of supply system?

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In single phase supply, 220V is voltage diff. between Line & neutral while, In 3 phase supply there are 3 supply lines phase shifted at 120deg from each other, so net voltage diff. (the phase resultant) between two phases in accordance with phase angle of 120deg is 440V.

However in 3 phase, 4 line systems having 1 neutral also, the voltage diff. between neutral and any of the phase is 220V...

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Pasupulati. V. N. Sekhar

  • Jan 9th, 2012

In case of 1Ph supply voltage is measured in between Phase and neutral, but where as in the case of 3Ph supply it is been measured in between two phases of line which differ each other by an phase difference of 120 degrees. So resulting net voltage between two lines which differ each other by a phase difference of 120 degrees always hovers around 440V

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  • Feb 17th, 2012

440v is the line to line voltage, there is 230v for phase to neutral. So both 230, 440 volts is common operating voltage recommended by Indian standard rules. If our application required 660 volts, Just we step up the voltage by suitable step up transformer.

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Umer Farooq

  • Sep 16th, 2014

440 volts instead of 660 volts in 3 phase is because of 1 phase is always zero at any instant of time therefore we cant use 660 volts in 3 phase

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  • Jun 9th, 2015

We are using star connection for generation system so there is a neutral point. How can you say that in 3 phase the one phase is neutral?

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uddhav kumbhar

  • Nov 12th, 2016

Voltage measured by two point this is basic angle is not taken or in phase voltage resultant voltage is 0, so take angle between two phases.

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Sankareshwaran V

  • Mar 13th, 2017

Their should always be a return conductor to close the circuit, so in 3phase one of the phase act as a return conductor.

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Asim Bilal

  • Jun 22nd, 2017

It is neither 440v nor 660v, it is 381v by formula 220v*underroot 3=381v

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