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Old 17th Oct 2020, 7:31 pm   #20
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 1,721
Default Re: Wiring a 110V two-phase motor?

I suspect that this might be expecting a true two phase supply with a 90 degree phase angle between phases. Possibly the red pair to one phase and the black pair to the other phase.
In that case there should be a low resistance between the two red wires and a similar low resistance between the two black wires. Between red and black should be open circuit.

Two phase was never popular in the UK and is now believed to be extinct.
Still exists in the USA, but rare and becoming rarer. Most utilities wont supply 2 phase these days, except to existing customers already so served.

Present day USA mains supplies are usually 240 volts, with an earthed center tap to gibe 120 volts for lighting and small appliances and 240 volts for heavy loads.
Some are two phases and neutral derived from a 4 wire 3 phase system, these give the same 120 volts for lighting and small appliances but with 208 volts for heavy loads rather than 240.
In common parlance in America "two twenty volts" often means a supply that is either 208 or 240 volts but the person speaking does not know or care which. May also refer to an appliance intended to work from either 208 or 240 volts as in "I need to buy a two twenty volt stove"

Neither of the above is a proper substitute for a true two phase supply.

Single phase to true 2 phase converters used to exist, but I doubt that you will find one these days.
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