Semi-dead motor

[M0BNDParticipant @m0bnd]

New motor on ebay ….. **LINK**

[M0BNDParticipant @m0bnd]

[Sub MandrelParticipant @submandrel]

Hi Mobnd,

Is the motor actually blown, or is it just that the red wire worked loose and has sparked to create the mess?

Neil

[M0BNDParticipant @m0bnd]

A good question.

I am not sure, but there is no longer a way of attaching the wire to the motor as I see it. I remember looking here when I first started using the lathe and checking all connections as the motor has never sounded correct since I have owned it (about 2 years now)!!!
There are a couple more photos in the album I have created which may or may not show more detail.

Andy.

[Keith LongParticipant @keithlong89920]

Hi Andy

It looks from the photos as though the wires down into the winding are fairly intact so with a bit of luck most of the problems will be in the terminal block and housaing. Make a note of what wires are still connected to what and then do continuity and earth checks on the wires to the windings. If the checks come out OK you should just need a new terminal block, which shouldn't be a problem really as all it is, is a means of connecting the wires up to the mains. I'd go for a ceramic connector personally which are readily available from most electrical merchants. If yo're not confident about checking the motor yourself have a look in the local directories to see if you've a rewind shop close by and get them to give you a quote for a quick inspection followed by repairs. It could well be cheaper than the new motor that you highlighted on EBay. I had a 1HP sigle phase motor done last year, full check over, supply and replace bearings, and some rewiring, £200 with a guarantee on the work.

Keith

[M0BNDParticipant @m0bnd]

Hi Keith.

Thanks for the reply, I didn't contemplate using a repairer but I will call a few 'local' motor menders on Monday – they may offer an exchange motor? They all seem around 25 miles away from where I am in a quick Google search. The replacement motor on eBay is 'only' £127 delivered so a bit cheaper than the £200 as you have paid previously. If, however it is a little ceramic or similar insulator that is required then I could easily do that work myself.

Andy.

[Keith LongParticipant @keithlong89920]

Hi Andy

The reason I suggested a motor repair shop is that the earth check needs to be done with a high voltage eg a "Megger" not just checking for earth leakage or lack of it with a normal ohmmeter. The motor I had repaired was a big, heavy "vintage" Brooks motor that has quite a bit of inertia so giving a flywheel effect. The price that I gave included the new bearings so I though it wasn't too bad, especially for the peace of mind with what would otherwise have been an unknown quiantity. What they did for me was to run the electrical test first, free of charge, and then quote for the repairs, they should do that for you as well so that you can make the choice between repair or replacement on the basis of hard facts.

Keith

[M0BNDParticipant @m0bnd]

Posted by Keith Long on 13/04/2013 14:54:15:

Hi Andy

The reason I suggested a motor repair shop is that the earth check needs to be done with a high voltage eg a "Megger" not just checking for earth leakage or lack of it with a normal ohmmeter. The motor I had repaired was a big, heavy "vintage" Brooks motor that has quite a bit of inertia so giving a flywheel effect. The price that I gave included the new bearings so I though it wasn't too bad, especially for the peace of mind with what would otherwise have been an unknown quiantity. What they did for me was to run the electrical test first, free of charge, and then quote for the repairs, they should do that for you as well so that you can make the choice between repair or replacement on the basis of hard facts.

Keith

Ah, ok all understood. As said, I will call a few on Monday. They all seem to be in the Poole/Bournemouth area.

Thanks.

Andy.

[Speedy Builder5Participant @speedybuilder5]

The motor plate says capacitor start + capacitor run?? Are the capacitors OK, and were they the cause of the burn out ?

[M0BNDParticipant @m0bnd]

Hi Speedy, all capacitors appear to be ok – clean with all contacts etc in one piece.

Neil (stub) – I showed the photos to a retired engineer who has their own machines and he suggested someone very close to get an insulator block and suggested the very same as you about a loose connection. I will try that first as it will be the cheapest at the moment.

Andy.

[AndyfParticipant @andyf]

If I were you, I'd experiment, taking careful note of what connects where and to what else, then wire the whole thing up with chocolate block connectors and give it a brief trial run. If it works OK, then all you need is a connector block which is more heat-resistant than a choc block.

If uncertain about working with mains voltages, ignore what I just said, but if you can wire a plug you should be OK.

Andy

[M0BNDParticipant @m0bnd]

Thanks Andy F.

I have already taken more detailed photos and drawn the wires on paper. I am ok with mains voltage and I am prepared to buy another motor if all fails!!! The chocolate block idea is a good one, I just need to convert the crimp terminals to get them into one chocolate block hole…. Should be easy enough – maybe just buy some really big chocolate blocks!!! Thanks for the idea and tip.

Andy S.

[AndyfParticipant @andyf]

Andy S,

Well, it needn't be choc blocks. If physically possible (in the sense that there's enough spare wire) a lump of wood with woodscrews through the connectors which need to be mated would work, though the screws shouldn't stick out of the back of the wood in case of -zap!-

I suppose that' would be breadboard construction at its simplest.

But from the photos, it looks like only one connection has blown. The rest of the discolouration may just be magic smoke condensate. Try connecting the loose red wire to the wire it mates with and leave all other connections in place. Maybe use a short screw and nut through the two connectors, and plentiful insulating tape.

Andy

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

The rule: Bad contact -> high resistant -> fire. After you has fixed the problem, be sure all connections is secured good contact (clean surfaces), turn firmly at all contact screws (do not overturn then treads is stripped of)..

[Brian WoodParticipant @brianwood45127]

Good morning all,

Not a direct comment on the thread as it stands, but how many of us have rectified 'failures' with domestic appliances on non moulded 13 amp plugs, in that most are caused by nothing more or less than just loose terminal screws on the pins?

And for that matter, why is it that the Neutral leg seems to be the one most often affected?

Any answers?

Brian

Edited By Brian Wood on 14/04/2013 10:39:54

[M0BNDParticipant @m0bnd]

Temporary (or maybe permanent?) repair…

… and she runs again…
…just one last problem to sort out…

This horrible banding – ew!!

A massive thanks to all comments on here, as without them I would have blown £127 on a motor that was not required.

Andy.

[Anonymous]

I had multi-start banding like that on silver steel and stainless steel; turned out to be a badly worn hold down bolt on the compound slide.

The first question would be; did the lathe produce the banding before, and if not, what has changed?

Regards,

Andrew

[M0BNDParticipant @m0bnd]

I think I will start another thread as this will get mixed in with a different subject matter.

Andrew – When you say a badly worn hold down bolt, what do you mean?

Andy.

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

You are not alone with screw connections in electric motor. I saw the electric motor with screw connections allready mounted from factory, no problem. Secure the screw connection at place in the electric motor against vibrations who will make fatigue in the wirings and burst again next time. I would recommend the screw connections maked for 16 amper instead 10 amper current to be sure there is not risk to overheating the screw connections by load under hard work.

Edited By Jens Eirik Skogstad on 14/04/2013 12:08:32

[M0BNDParticipant @m0bnd]

Thanks Jens.

I will pop to our local electrical factors as recommended by an engineer where I live to see if I can get the correct part.
I see the motor is rated at 10A and if I cant get the correct part then will use a heavier duty connector block.
Thanks for the advice again.

Andy.

[AndyfParticipant @andyf]

Andy S,

Glad you're up and running again at little expense. As you say, it might even be a permanent repair – did the motor ever get noticeably hot when worked hard for a while?

You might even consider soldering wire directly to wire, having first slipped a bit of heatshrink tube over one of the two so, once a joint is made, you can use the heatshrink to insulate it.

Andy.

[M0BNDParticipant @m0bnd]

Andy F – It's a possibility later on to solder, I will run for a while and keep an eye on the joints that are there at the moment.
If I can pick up another insulator I will use that, if not I will consider soldering or uprate the existing chocolate block to a slightly greater rating, make a plastic enclosure with a perspex lid and screw that to the motor where the existing mounts are.

Andy S.

[AndyfParticipant @andyf]

10A choc blocks should be OK, provided the motor doesn't get hot enough to soften the plastic. I used 10A ones to connect a cable to a 2HP DC motor (which doesn't get warm). The other end is connected to a speed controller by simple push-on spade connectors. No magic smoke has appeared over the last three years.

Alternatively, search Ebay for "ceramic connector block" , when various possible candidates will appear.

Andy

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