Which is best single phase motor – 2 pole or 4 pole

[AjohnwParticipant @ajohnw51620]

My small one came from B&Q years ago. The Einhell has a 50L tank but it stands on end. Part of the attraction as it takes up less floor space.

This page shows them all

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This the one I just bought – or my wife did for xmas.

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Looking at what some other plasma cutters need that one might do it. I don't think my small one would produce anywhere near enough air. 100l/min at 4 bar may be a touch too much but hardly any margin at all.

What I don't know yet is if it will actually do it or how long it will last etc. As wife bought it for me I'll have to sort it out if it falls short. I've never bought this brand name before but have noticed that some of the larger sellers have offered it in the past. Screwfix and Toolstation and others I think.

John

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[bodgeParticipant @bodge]

John

many thanks for the info , not too sure how to use the tech data though, it seems like they are saying ,at 4 bar = 107 litres free air per minute, . at 7 bar = 76 l / per minute

I take it thats how you are reading it too ? or i have i missed something ?

I take it you are planning on using it for plasma arc cutting on the Tig machine, watched a few you tube vids a week or so ago but didnt take notice of the compressor size, was to busy looking at how the plasma cutting went ,

Knew someone a few years ago, had the same type of m/c but with smaller 25 l air tank he had no problems with it at all though he was only running an air nail tacker for upholstery work .. I suspect it will depend on the cleanest cut you can get for the minimal amount of air pressure.. hope it works out OK……………b

[bodgeParticipant @bodge]

Posted by Michael Briggs on 04/01/2017 10:10:31:

I am sure there will be other members on the forum that can throw more (accurate) light on this than I can. I suspected that a two pole motor would be noisier than a four pole, looking in an ABB publication they are quite a lot noisier though given the racket my Clarke compressor makes, you probably would not be able to tell the difference. Regards, Michael.

Hi Micheal

I think the perceived difference in noise between 2 pole & 4 pole is more to do with pitch rather than db , made all the worse by having the the pump head & motor bolted to the receiver which amplifies things a bit, in my case i knew that was going to be a problem so i had flexible hose made up at the local hydraulic works about 2 metre long so i could remote mount pump & motor from the receiver , really quietens things down………b

edit for typo error……..b

Edited By bodge on 04/01/2017 18:08:48

[AjohnwParticipant @ajohnw51620]

I just read the details of the air needed from a similar dedicated plasma cutting machine. This one for instance which is a 30amp unit. The one I looked at was 25amps max. There isn't much difference.

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It's turned out to be an expensive add on (for my wife) for what I want which was just tig and stick. Being fair about that though buying Xmas presents for me is always a problem and if needed I'm pretty sure I can boost it up by fitting something like a Clarke 2hp twin cylinder pump head. These go on Clarke's industrial blue range.

As some one mentioned in the 3in1 thread it's duty cycle isn't terribly good but I will probably set it up with the regulator on the compressor set at 5 or 6 bar and the one on the unit at circa 50psi. The compressor cuts back in at 8 bar. Might be ok. Depends on how long the torch needs to be on.

It's a hell of a spec for this type of compressor – this one is similar

**LINK**

I spent some time on that site looking to see what could be expected from different sizes of compressor. There are various versions of the one I bought though and numbers differ. Einhill do give a number which is unusual so decided to give it a go,

Use – I might do an engine Jason style some day and being able to profile plate would be useful. Also other things. The idea of clean cut is immediately suitable for welding. The deeper figure they give isn't. It seems that the way to use them is to move the torch at a rate that causes narrow angle sparks to come out of the back. Too slow and the angle will widen. Add the torch needing to be about 1mm from the work I wonder why they don't all come with a guide to space the torch off the work. I'm thinking about something based on a pipe clip. Simple as making anything at the moment is a bit difficult.

John

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Edited By Ajohnw on 04/01/2017 19:40:03

[Michael BriggsParticipant @michaelbriggs82422]

Posted by bodge on 04/01/2017 18:02:36:

Posted by Michael Briggs on 04/01/2017 10:10:31:

I am sure there will be other members on the forum that can throw more (accurate) light on this than I can. I suspected that a two pole motor would be noisier than a four pole, looking in an ABB publication they are quite a lot noisier though given the racket my Clarke compressor makes, you probably would not be able to tell the difference. Regards, Michael.

Hi Micheal

I think the perceived difference in noise between 2 pole & 4 pole is more to do with pitch rather than db , made all the worse by having the the pump head & motor bolted to the receiver which amplifies things a bit, in my case i knew that was going to be a problem so i had flexible hose made up at the local hydraulic works about 2 metre long so i could remote mount pump & motor from the receiver , really quietens things down………b

edit for typo error……..b

Edited By bodge on 04/01/2017 18:08:48

Hello Bodge, in a Leroy Somer document the noise for 56 size frame single phase motors expressed as sound power level (LwA) is 68 for a 2 pole motor and 58 for a 4 pole motor. Sorry to be a bit pedantic, may be of interest to someone. Regards, Michael

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