three phase for domestic application?
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chris_on_tour2002
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three phase for domestic application?

by chris_on_tour2002 » Tue Dec 02, 2008 1:11 am

hi all,

i've been offered a very nice bench saw and band by a kind friend who is clearing out his workshop.

i want to put them in an outbuilding at the back of the garden. problem is they are both 3-phase.

can this be done? somebody mentioned to me that it would require another feed directly from the street. is there any other solution?

i am waiting for my friend to get back to me with details of the wattage of the two machines (which, incidentally, would never be run at the same time) so i can work out the draw.

i have a 10mm T&E (appx 50 metres/150 feet long) that is in place but does not yet feed the outbuilding. i am going to connect it up when my consumer unit is updated to 17th ed.

the 10mm will go into a separate unit in the outbuilding and feed 3 double sockets and a smattering of garden lights and a small water pump for the water feature. could this in any way be used in my plans for a 3-phase? i am guessing not.

matthewm1965
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Joined: Sun Nov 09, 2008 12:28 pm

by matthewm1965 » Tue Dec 02, 2008 10:45 am

You can buy single phase to three phase converters that are ok to use with motor loads.
They can be expensive, depending on the motor size. I think the smaller ones may be available as plug & socket connections, therefore avoiding any fixed wiring.
Most variable speed drives are available as 1 in 3 out configuration for the smaller sizes. Again not cheap.
Matt

ericmark

by ericmark » Tue Dec 02, 2008 11:30 am

A lot depends on what motors are fitted. All motors tend to be duel voltage the larger ones will normally run delta at 400 volt and the star voltage is 695 volts although never used at those volts it allows lower current draw when starting but smaller motors are star at 400 volt and delta at 230 volt these can be run with an inverter on a 230 volt supply the inverters are relativity cheap around £100 depending on exact type use. Although inverters are available which can power 400 volt motors from 230 volt single phase these are a lot more expensive. To use the inverters some rewiring may be required moving links in motors etc and even in some cases new transformers for the control circuits but in general it is cheaper and more available than getting a 3 phase supply.

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