1ph to 3ph Electrics

I need to provide 3 phase electricity from a single phase supply to one motor of 1/2 HP that has a dual voltage on the motor plate which states that it is an AEI motor 220/250v to 380/440v at 1.6/ 0.9a.

I think I've found the correct converter to do this but the whole subject seems to be full of questions.e.g. some converters supply 240V per phase, does that mean it's a 220v to 720v converter?

I think I need a 240v to 440v converter, but I don't need infinitely variable speed as the belts and pulleys on the machine will give the speeds that correspond to the ones on the machines data plate.

Can someone provide a simple explanation?

Brian

Brian

Do you really need 3 phase? It may be cheaper to replace the motor. If you are not used to 3 phase, bear in mind it is LETHAL if you do not RESPECT it. 240volts is bad enough, but 440 volts.... You will see lots of posts about 3 phase on this site - I wonder if it is legal to permanently wire in motors etc ??
BobH

Brian,

There are two simple options.

You can swap the motor out for a single phase version, if you can find a drop in replacement, or, rewire the motor connecting the windings in Delta fashion ( google star-delta wiring) and buy a 1hp inverter 240 v ac in and 3 ph out...

There are plenty of suppliers, Engineers Mate, Drives Direct...( I've used both suppliers...usual disclaimer...)

Edited By John Rudd on 20/04/2018 20:51:36

The most common VFDs are supplied from 240 volts single phase and supply a three phase output that is 240 volts phase to phase. You can get more expensive ones that will supply 415 volts phase to phase so that you can use a motor that cannot be configured for 240 volts phase to phase. The motor you have can be configured in a delta connection for 240 volts phase to phase or in star connection for use with 415 volts phase to phase.

Les.

Thanks for the reply Bob. Unfortunately the motor is a special flange mounted one so may be difficult to replace and I prefer the smoothness of 3ph

I am very familiar with 3 phase as I used to run a machine from a static converter and then moved house to find three 400A fuses coming through the floor in the meter cupboard! To say I was overjoyed was an understatement!

I'm not an electrician but always prefered working 3 ph rather that 1 ph. I'm VERY respectful of electricity and so take no chances.

Brian

Edited By BDH on 20/04/2018 21:00:33

Brian,

If you have 3phase to the house why run an inverter ???

Philip

Edited By Philip Devonport on 20/04/2018 20:59:23

Many thanks for the reply Les, which sets my mind at ease. Your info matches something I have read and the instructions that come with the inverter I am looking at show the two types of connection needed.

I definitely owe you one.

Brian

Philip, I should have said that I've moved house again and sadly, there is only a single phase supply here.

Brian

Brian,

That would explain it. Just be aware you need to keep the inverter out of tight spaces for airflow and pretty clean as they do attract dust/debris.

Philip

You said in another post that you were only a few miles from Drives Direct. Just take the motor off and take it along to them when you buy the inverter. Probably best to arrange an appointment first. Your motor is the type that can be converted to Delta.

Should you choose to go to Drives Direct, I've always found Dave very helpful and will assist any way he can...

Edited By John Rudd on 20/04/2018 22:37:09

Thanks for the info on Direct Drives John & Bazyle, their website has quite a bit of information on the different types of converter.

http://vi.vipr.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=152981156478&t=1455483105000&tid=310&category=41952&seller=drives_direct_nottingham&excSoj=1&excTrk=1&lsite=3&ittenable=false&domain=ebay.co.uk&descgauge=1&cspheader=1&oneClk=1&secureDesc=0&oversion=acd0058

Brian

Hi , buy the MAP publications book on Electric Motors. There is a chapter that tells you how to run 3 phase motors on single phase. I have had my lathe running like this for the last 25 years with no problems.

Just thinking out aloud here probably make my self look silly but I am used to that :P

How does home insurance stand on 440V etc.

If you have home insurance it might be worth just looking through it to make sure they are ok with 440V machines lets be honest theres not many people who have 440V items in there home they might not be willing to insure it as its realy classed as industrial?.

If you change the motor from star to delta connection as Jim Cox explains in his book on Electric Motors then the motor is running on 240 volts.

I changed the wiring from star to delta on my old milling machine and connected a suitable capacitor across two of the windings and ran it on single phase.

I believe this topic is covered in the workshop practice series on electric motors. You only get about 80% of the rated power but I never had a problem using the machine.

Edited By Vic on 27/04/2018 15:00:16

In my experience home insurance doesn't want to know about any machine tools. One, they rarely insure anything of significant value within garages or sheds. Two, they're utterly clueless about what a lathe or milling machine is, so there's no way they will insure it. As it happens almost all my machines run on 415V 3-phase. They, and my part built engines and material, are insured via Walter Midgeley, separate from my house insurance. The issue of single or 3-phase didn't come into the quote, simply estimated value.

Andrew

Andrew Johnston

ah ok

Also thanks for info as I am looking at getting insurance for the machines etc in my garage shall look up Walter Midgeley.

The UK 3 phase distribution side supply is 230v phase to neutral, 415 phase to phase. Arguably therefore it is no different in terms of insurance hazard from standard single phase mains.

Many thanks to all for the input; I decided to go with the inverter from Drives Direct which is a 10 minute drive from me and they are VERY helpful.

I wasn't too sure if I needed any extra components or exactly which wires went where but they have a scheme where you send them pictures of your machine motor connections etc and they provide instructions on how to wire it, and all for £25.00, a lot cheaper than an electrician.

Brian