Single to 3 phase transformer on eBay

[adam2]

Options could include,

 

1, look for a machine with a single phase motor.

 

2, buy the three phase machine and use an inverter with single phase input and three phase output.

 

3, buy the three phase machine and power it from a three phase generator. Worthwhile if you have other uses for a generator such as event use, or backup power.

 

4, pay the price for a three phase supply.

 

For options 1 and 2, make certain that the single phase supply is big enough.

 

 

 

[themadhippy]

the best approach is to accept that it cant easily be done.

 

wot ever happened to the ole rotary convertors? Big old single phase motor bolted to a 3 phase generator

[Jivemaster]

The unit from Machine Mart that I linked above is one of three that they sell for doing exactly this. Also it's the same cost as the postage on the ebay one.

 

The only limit is the power available in your workshop for that and everything else. Fractional HP motors work OK on single phase, but bigger motors do better on three phase.

 

Motor start current may be an issue.

[adam2]

the best approach is to accept that it cant easily be done.

 

wot ever happened to the ole rotary convertors? Big old single phase motor bolted to a 3 phase generator

 

 

My post specifically mentioned that as a possibility, but I stand by my remark, also in the post "that the costs, complications, losses and potential starting problems" render it unviable in most cases.

 

 

 

 

[James Remo]

Lawrence of Backroom passed away, his son Jack is now running the business (as well as being a rather good rock and roll stage manager) Still my first port of call for anything transformer based.

[andy™]

To work a three phase motor from a single phase supply, purchase a 3 phase motor drive inverter with single phase input. These are widely available.

 

 

but are almost always 230v 3 phase, no good on a 400/690 TP motor. it would need a 230/400v TP motor which are available but not as common

 

Thanks all,

 

The reason for this enquiry is that I'm considering upgrading my table saw to a much larger machine.

 

 

This kind of thing: https://www.rjmachin...d/altendorf-f45

or this: https://www.ebay.co.uk/itm/Striebig-Compact-11-Type-4164-Vertical-Wall-saw-Excellent-9950-VAT/332823157913

 

Getting a 3-phase mains supply installed will cost as much as the machine.

 

Logically I need to lower my sights.

 

not many options on SP. youd be best getting something thats designed to SP. easiest option (at least on the wall saw) would be to replace the motor with a SP motor. may need controls altered too (might have a 400v input control transformer, youd need to change it to 230v)

[KevinE]

You sound like you're looking for a phase converter and that ebay thing is one of them, but if communicating with the seller is appearing awkward, I'd look elsewhere.

 

Phase converters will take the 230VAC and convert it into a dirty approximation of a 3-phase 415V supply, but they aren't perfect. For a table saw, they will also take a huge amount of power off the 230V as the saw accelerates up. As an example, a client of mine bought one for his saw in his garage and it kept tripping out his 32A mcb. We measured the current and the electrician decided it needed a 60A feed. It still dimmed the house lights as it started up!

 

If the 3-phase saw you are looking it has a motor of under 4kW, it is probably dual-voltage 230/400V which means you can wire it to feed it with a VFD (inverter drive). These have the ability to limit their acceleration curve and current to a sensible level, and synthesize a genuine 3-phase sine wave, but at 230V. The motor will run smoothly and without inrush off an inverter drive.

 

A single to 3-phase transformer per se does not really exist.

[adamharman]

As one of the machines you've linked to is a vertical panel saw, I assume you've only cutting sheet materials?

 

In which case you don't need an enormously powerful motor - 3kw (as the vertical one in your link) is plenty so I'd be looking for a single phase machine.