Replacement lathe motor thoughts?

[Chris152]

Mine's faltering sometimes - at the moment it's working fine, but I don't feel confident it'll last (it was playing up for several days, then the last couple it's been ok). The brushes are chipped and apparently that can mean a damaged commutator. My plan is to keep running it, but be ready with a plan to replace, which is what I now expect to have to do. (repairs look very expensive, too.)
It's a Leeson, .75 HP DC with AC converter and speed control (Dart). I've been quoted £642 for a replacement motor, imported from the US.
https://www.raptorsupplies.com/pd/leeson/108369-00That's a lot of money to me. I've searched for alternative DC motors but, not knowing much about these things, am not sure what I'm looking for. Seems to me that whatever I get really needs to fit easily (two bolts into frame/ tension adjuster).
Any advice much appreciated.
C

ps the quote I received for the motor describes it as .75 hp; some links to that spec say the same, others say .75 kw.
Sorby info says the lathe had a 1hp motor without the speed control, but doesn't specify the motor that came with speed control, which mine has:
http://www.lathes.co.uk/sorby/Confused.

 

[Duncan A]

Fit new brushes, very carefully clean between the commutator segments. Don't do anything to the surface of the comm unless it is extremely uneven, then do the absolute minimum to remove any sharp edges or major undulations that prevent the brushes from seating.
The comm surface should not be bright; it should have a dark patina.
Duncan

 

[Chris152]

Thanks Duncan. Here's a pic of the commutator through a brush access point - can you advise what to do to clean it?

 

[Chris152]

ps here's a pic of the chipped brush - the other is better.

 

[Duncan A]

The colour looks OK, the surface is flat but it looks as if it is scored due to the ingress of something. It may be that this also chipped the brush.
I would write to the motor manufacturers and ask them if they can supply new brushes (get two sets) or at least advise the grade of carbon and dimensions.
It's difficult to tell from the picture how bad the scoring is, but I think I would lightly abrade the com with glasspaper (nothing with metallic grit!) to try and reduce the scoring. Clean thoroughly and then make sure that the slots between the comm segments are below the surface of the copper and free of grit and carbon deposits. Use an old hacksaw blade if necessary to clean out the slots.
Check the brush springs are still sound and hold the brushes onto the comm.
At present, the brush carriers look rather grubby. Clean them up and make sure that the brushes are free to move up and down to follow any out-of-roundness on the comm.
All of this is easier with the motor stripped down to expose the comm but, if you feel this is beyond your competence, just clean everything thoroughly, fit new brushes and see what happens! The whole point of using carbon brushes is that they will bed in and conform to a significant amount of irregularities.
Keep a look out for sparking between the brushes and the comm. There may well be some present but it should reduce with time - ideally should be nothing but that's hard to achieve.
If the motor is reversible, run it in both directions for a good length of time. Bizarrely, a decent load is better than a low load as the flow of current helps to lubricate the brushes.
Duncan

 

[Chris152]

Than you Duncan. Really helpful.
I'm going to order up the brushes and keep using as it is until it starts to falter again, then I'll try the cleanup/ new brushes. Fwiw, I did look inside as it was running and saw no signs of shorting at all - maybe that'll change if the fault recurs.

If anyone has any suggestions for a change of motor in case that doesn't work, please advise so I can start saving the pennies now!

 

[Cabinetman]

I have been running my lathe on an old washing machine motor for years, no fancy speed control though, it’s held in place with two home-made hoops of threaded bar – certainly a lot cheaper than what you have been quoted !
And you won’t need to start saving the pennies ha ha

 

[Chris152]

I have been running my lathe on an old washing machine motor for years, no fancy speed control though, it’s held in place with two home-made hoops of threaded bar – certainly a lot cheaper than what you have been quoted !
And you won’t need to start saving the pennies ha ha

Maybe I can rig it up like one of those multi-tools, do the laundry at the same time as turning...

 

[Robbo3]

+1 for Duncan's advice.
A quicker & easier method is to use a commutator cleaning stick often referred to as a brush seater, if you can find a small enough one to get through the case. They are very delicate so go gently with a firm grip on the stick as close to the case as possible.
If you are capable of stripping the motor down this shows you how to clean up the com (mutator)
- How to Clean the Commutator of an Armature
If the slots need cleaning we used a hooked Stanley knife blade that had the outside curve flattened on the grinder to make a pull chisel.

 

[Reginald]

Mine's faltering sometimes - at the moment it's working fine, but I don't feel confident it'll last (it was playing up for several days, then the last couple it's been ok). The brushes are chipped and apparently that can mean a damaged commutator. My plan is to keep running it, but be ready with a plan to replace, which is what I now expect to have to do. (repairs look very expensive, too.)
It's a Leeson, .75 HP DC with AC converter and speed control (Dart). I've been quoted £642 for a replacement motor, imported from the US.
https://www.raptorsupplies.com/pd/leeson/108369-00That's a lot of money to me. I've searched for alternative DC motors but, not knowing much about these things, am not sure what I'm looking for. Seems to me that whatever I get really needs to fit easily (two bolts into frame/ tension adjuster).
Any advice much appreciated.
C

ps the quote I received for the motor describes it as .75 hp; some links to that spec say the same, others say .75 kw.
Sorby info says the lathe had a 1hp motor without the speed control, but doesn't specify the motor that came with speed control, which mine has:
http://www.lathes.co.uk/sorby/Confused.

Contact Newton Tesla they will be able to help you with this

 

[Chris152]

Thanks both.
Robbo - I don't fancy stripping the motor down, I really don't have a clue and am likely to do more harm than good - but will definitely look into getting a brush seater as you suggest. Problem now is, I can't find a uk supplier of the brushes. I wrote to Lektronix who say they can't supply brushes for the motor but I can send it there to have them fit them. Hm.
Which leads me on another train of thought - I also wrote to Haydock last night about a 3ph plus vfd for the lathe, waiting for a reply.
Reginald - Newton Tesla seem to do dc with inverters, so I could either just get a motor (if my current inverter will work with it) or I could get a complete kit - still way cheaper than buying a new Leeson from the US.

A new motor is just my fallback plan, but tbh the more I look into Leeson, the less I'm inclined to buy another - imported to order from the US, what kind of warranty will it have, where do I take it for repair, I'm struggling just to get brushes for it. So a main dealer of a make, with stock and parts seems relatively attractive.

 

[NetBlindPaul]

I would not go to Lektronix, but then again that’s personal because the former MD/Owner tucked me up imho.
If you are not up to the repair yourself I would look for a small local motor repair company.
I use one about 40 miles away from me because he is good, and a friend also.
My 2nd choice is about 10 miles awsy.
Both small, one is a 2 person company, the other is a family business with about 6 ish people.
If the motor is running it should hopefully just be a strip, clean, test, new brushes and bearings and rebuild.
The motor repair companies have sources for brushes away from the motor OEM.

 

[Chris152]

Thanks Paul - what towns are they in/ near? I'm in South Wales, too. I did look online for local specialists but had no joy.

 

[Fergie 307]

For brushes try any motor repairer, or once you know the size have a look on e bay or similar, if need be you can get bigger ones and grind them down. Please don't use sandpaper on he commutator, bits of abrasive will inevitably come away and end up in the motor. Use a stick as advised.

 

[Cabinetman]

I know this isn’t the same but it might give you an idea of costings, I recently took my three-phase dust extractor motor in to have new bearings fitted, and this involved getting the impeller off the end of the motor, (I tried and it was well stuck on,) £220 including VAT. Not a small amount but not wildly expensive either – I was happy. Ian

 

[Chris152]

I know this isn’t the same but it might give you an idea of costings, I recently took my three-phase dust extractor motor in to have new bearings fitted, and this involved getting the impeller off the end of the motor, (I tried and it was well stuck on,) £220 including VAT. Not a small amount but not wildly expensive either – I was happy. Ian

If I can get this one fixed (once it plays up again) I'd much prefer that. Apart from the money (which is important), the motor fits perfectly with the minimal look of the lathe - hardly no.1 priority, but I really like the way it looks, and saw one that had a 3ph conversion and controller, I thought it looked hideous in comparison. If it needs a new motor tho, I could be persuaded to compromise

 

[Trextr7monkey]

Hi I hope thsi is not mistaken for an ad but there is a brilliant firm in Carlisle who fix motors and instal whole factory control systems worldwide. It’s a family business that has moved with the times but as Carlisle has lots of factories involving motors there’s nothing that they can’t do and they have racks of motors waiting to go. There a bloke full time fixing power tools for tradesmen and public alike. I would suggest you contact them and they will no doubt be able to assist.
It’s called Parkgate Electrical and Mr Park is still there.
Hope this is of some help

 

[Mick p]

Hi you could try Solent rewinds in Portsmouth just a farther and son great service.

 

[Chris152]

Thanks Mick - Paul's given me a couple of good recommendations that I can drive to fairly locally, and the combination of his recommendation and the fact I won't have to pack it up and post makes that the best option at the moment. Right now the motor's working fine again (touches wood!), and I seem to have a decent plan for sorting it if it goes wrong again. Time will tell...