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Single phase reverse electrical genious required

Reversing Single phase switch attatched to motor

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Eric Arthrell10/05/2017 16:24:54
47 forum posts
19 photos

Martin Electricity can be fatal. silent no smell and deadly

If you are not 100% sure pay an electrician to do the job.

Brian Oldford10/05/2017 17:02:11
395 forum posts
4 photos

Having followed the thread off and on during its progress, the absence of a centrifugal switch make me wonder if it could be a shaded pole motor. They are often used on machines that do not need a lot starting torque. A fan or a spindle moulder might such a machine. They are not reversible.

Michael Gilligan10/05/2017 18:56:19
11464 forum posts
492 photos
Posted by Martin Newbold on 10/05/2017 15:49:44:

Read up about the labours of Sisyphus before you start rewinding that motor? can you provide a link please?


Martin ... allow me: **LINK**


Edited By Michael Gilligan on 10/05/2017 18:56:39

SillyOldDuffer10/05/2017 19:57:04
3126 forum posts
628 photos

Hi Martin,

I hope you won't take this amiss but you remind me of a very good friend of mine. He's a smart cookie, very good at most of what he does and very confident. He has a blind spot though; he thinks he's good at everything, and no-one is that! Once in a while he comes a cropper and can't believe he got it wrong.

Electric motors are not simple and they are not all alike. I find them very confusing. Reading back through the thread I see a couple of places where you asked for help and then missed requests from experts like John and Les asking for more information. What they were trying to do was establish what type of motor you have and what the various connections are for. I can't see where you answered their questions, which is why Les suggests you've been guessing.

Later you published a series of wiring diagrams: I didn't realise these were asking for help, rather I thought you were telling us that you had got the answer! You seemed to be making good progress,

Francis (who knows a bit!) advised against reusing the old motor wiring. He's absolutely right. Once a motor has cooked all the insulation is compromised. He's trying to help - he doesn't want you spend a lot of effort repairing a motor that's likely to fail again.

Others have tried to explain that rewinding a motor by hand is seriously difficult to do. It will take forever, and it may not work when you've finished, even if the insulation is OK. It's akin to me (a very inexperienced Model Engineer), saying I'm going to start by free-lancing a 2-10-2 locomotive in 9" gauge and is it OK to soft-solder a boiler made out of Titanium.

If I were you I'd start again. Buy a new motor with a data sheet. I'd try with a VFD and 3-phase, they do work despite your first bad experience. Once bought I'd come back on the forum and start a new thread asking what to do. John, Les and others have successfully helped many others with lathe motor problems. The secret is for you to carefully answer their questions and patiently take their advice so that they can guide you through the maze.

I was going to advise you not to get discouraged. Looking back I don't think you need that. Your adventures with electrics may not have gone well but no-one can criticise your determination whilst the photos show you've done a fine job on the mechanical side.



Mike Poole10/05/2017 20:03:06
1406 forum posts
41 photos

We used a material called Elephantide to line the slots and red fibre to close the slot. The coils were bound after installing in the the slots with flat cotton tape. The wire size is measured after the coating is removed by burning off as the size does not include the coating.


Neil Wyatt10/05/2017 21:07:03
13849 forum posts
583 photos
68 articles

I am worried that this thread is encouraging actions that could prove fatal.

When it comes to advanced work with the mains, and I definitely include motor rewinds in that category, you don't just need to know WHAT to do, you need to know why you do it.

There's been a warning not to reuse old coils because they may be damaged. They may well not be broken, or even shorting out when tested with a multimeter, but unless they are tested with a proper high-voltage insulation tester like a Megger, there is NO WAY of knowing whether they are going to be safe when running.

Any cut corners could easily lead to a third motor failure, which could have more drastic results than the first two.

I don't want to lose any forum members...


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