30 3 phase .and 400v 3 ph question

440 volts phase to phase. 240 volts phase to neutral.

But in parts of the country that aren't supplied by the Long Eaton gas and peat board, its 415 phase to phase and 240 phase to neutral. Could (legally) be 400 and 230 respectively.

Mark Rand RTFM

I was looking at the standard yesterday and it`s actually 400 and 230 with a tolerance of -6% +10% which gives a spread of 376-440 and

216-253 and there is talk of making it -10 +10%. All to do with Europe of course.

Mark.

For interest?/reference in a European style 3 phase system

Vpp = SqRoot(3) * Vpn

Phase-Phase = 1.73 * Phase-Neutral

American low voltage stuff is actually 2 phase IIRC so the numbers work out differently

Richard

They don't use two phase!

Mark Rand RTFM

Acksherly, we do. The transformer to the house drops the power to 220 V, but each phase is 110v -- so some of the house is +110V to earth (or ground). The remainder of the house is -110V to earth (or ground). Just don't try connecting outlets in different areas together! 220 V appliances (ovens, driers & similar) use both phases. I've never tried running any of my motors that I brought from the UK on 220V -- suspect I'd have to try & do something too clever with the starter capacitors.

Regards Simon Carr

It's more correctly called split phase.

The common American system has the final distribution transformer with a 220V secondary and centre tap connected to earth.

The UK split phase system, as found on some farms, is simply 2 wires of a normal 3 phase supply plus neutral. I suspect that the supply companies don't install it now as split phase 415V motors have a close affinity to rocking horse shit.

Bob

Not any more,but it was used long ago. The first alternators at Niagara were 2 phase (90degree), 2kV, 5000hp, 25Hz. Converted to

11kV 3ph with Scott connected transformers or used 'as is' for one of Mr Tesla's new-fangled induction motors. Bloody confusing when I was a kid, there was a 1900s American text book in dad's book shelf which went into 2 ph (90degree) stuff in great detail and I had 1940s ARRL handbook that considered 220V 2 ph as if it was generated from a 110-0-110 single phase transformer.

Regards,

David P.

thank you every one ,

so am i correct in saying that if i create 3 ph 230 v with a rpc, make 230 v phase to ph, and something else to earth , as opposed t mains 3 ph ,which is 240 to neutral and 400 ph to ph ... and thats why i cant run a 400v motor off it .and to run a 400v 3 p motor , i need 400v ph to ph ,using a transformer ? thanks rober

-- ivanhoe

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