Windlass motor arm scorched

[Olly75]

Hi all

I had a problem with my windlass pulling very slowly, so long and short i pulled the motor off to check the brushes. There was significant debris inside (although about half the brush material was left) and 2 brushes were cracked. So following the oem maintenance advise I cleaned, epoxied the brushed back together and reassembled.

When I connected tje motor up to the batteries it still ran very slowly and got too hot to touch within about 30 seconds and a puff of the black smoke of doom came out of it.

So called in a professional who took it away and dissasembled. He messaged to say that the rotor arm is scorched1but it can be rerolled although its a very tricky job. Ive attached a photo, but does anyone have any experiemce of this issue, and how likely is a repair to be successful?

Edit! The indonesian sparky has explained that rerolling meams rewinding.. google translate failure!
The sparky also says the he will use a larger diameter wire as the original was too small. Does that seem like a good idea?

[Uncle Bob]

Originally Posted by Olly75

Hi all

I had a problem with my windlass pulling very slowly, so long and short i pulled the motor off to check the brushes. There was significant debris inside (although about half the brush material was left) and 2 brushes were cracked. So following the oem maintenance advise I cleaned, epoxied the brushed back together and reassembled.

When I connected tje motor up to the batteries it still ran very slowly and got too hot to touch within about 30 seconds and a puff of the black smoke of doom came out of it.

So called in a professional who took it away and dissasembled. He messaged to say that the rotor arm is scorched1but it can be rerolled although its a very tricky job. Ive attached a photo, but does anyone have any experiemce of this issue, and how likely is a repair to be successful?

Edit! The indonesian sparky has explained that rerolling meams rewinding.. google translate failure!
The sparky also says the he will use a larger diameter wire as the original was too small. Does that seem like a good idea?

Hi, I have had an old fashioned automotive generator rerolled and it was better than new. I have also had a couple of starter motors done and all good. Both jobs done by a trusted and GOOD auto electrician.

[coopec43]

Originally Posted by Olly75

Hi all

I had a problem with my windlass pulling very slowly, so long and short i pulled the motor off to check the brushes. There was significant debris inside (although about half the brush material was left) and 2 brushes were cracked. So following the oem maintenance advise I cleaned, epoxied the brushed back together and reassembled.

Why would you epoxy brushes back together? You are bound to damage the commutator doing that?

Why don't you buy suitable sized brushes to replace the originals? On one occasion I had to file down the brushes (slightly) to make it fit. (It has been working fine ever since)

[Jammer]

Originally Posted by Olly75

So called in a professional who took it away and dissasembled. He messaged to say that the rotor arm is scorched1but it can be rerolled although its a very tricky job. Ive attached a photo, but does anyone have any experiemce of this issue, and how likely is a repair to be successful?

Edit! The indonesian sparky has explained that rerolling meams rewinding.. google translate failure!
The sparky also says the he will use a larger diameter wire as the original was too small. Does that seem like a good idea?

Vocabulary-

Armature - the rotating coil of wire that you're calling a "rotor arm"

Commutator - the copper contacts where the windings end. The brushes press against it as it turns.

Rotor - The entire rotating assembly including the shaft, armature, and commutator.

From your description, it sounds like you have a four brush motor. That is, there are four brushes. This is common but there are some two brush motors and occasionally other configurations. In a four brush motor, half the power is carried by one pair of brushes, and half the power is carried by another pair of brushes.

Epoxy does not conduct electricity. Therefore, it is unlikely that the brushes you epoxied back together conducted electricity, and if they did, they probably didn't conduct very much of it. This means that the motor could only produce half the power it would have if it had been operating correctly. Such a motor is easily overloaded. The armature damage you see is the result of this overloading.

From your photos, the commutator is also burned slightly.

You have two choices.

Choice one would be to have the motor rewound with the original wire size, to replace the brushes, and to clean up the commutator with sandpaper or, if there's enough material left on it to allow it, by turning it on a lathe. I would not recommend changing the wire size because the wire size was probably not part of the original problem, and because it will not be possible to get the same number of turns of wire on the armature if larger wire is used. Reducing the number of turns may adversely affect the performance of the motor and (if the motor is series wound) cause the field coils to overload. The bearings should also be replaced, and the field coils checked.

Choice two is to replace the motor as an assembly, if parts are available.


Though unlikely, it's also possible you may be able to purchase a replacement rotor, either new or used. It should be installed with new brushes and new bearings, and the field coils checked.


For motors this size, typically it is cheaper to replace the motor than to have it rewound, at least in the USA and other areas where there is good parts availability and where labor rates are high. In remote areas you may be better off having it rewound.

[Olly75]

Thanks for the replies.

I epoxied the brushes back together because the motor maintenance manual from the manufacturer said thats what to do if the brushes were broken.....

I am very remote at the moment and i dread to think how long it would take to get a replacement motor. So will go with the rewind, but request the original size wire.

[skipperpete]

Originally Posted by Olly75

Thanks for the replies.

I epoxied the brushes back together because the motor maintenance manual from the manufacturer said thats what to do if the brushes were broken.....

I am very remote at the moment and i dread to think how long it would take to get a replacement motor. So will go with the rewind, but request the original size wire.

I’m wondering how and why a carbon brush could be epoxied back together, epoxy can handle a bit of heat before it fails ( wet exhaust components) but expecting a good bond and electrical conductivity from a component carrying fairly high amperage seems problematic.
Indonesia has a thriving auto parts industry even in remote areas, is it possible to get some starter motor brushes and cut em down to size. I’m surprised that the motor rewinder isn’t able to find something locally, brushes are a big part of his daily life. Indonesians have a politeness that extends to agreeing with oddball ideas from tourists to avoid offending them knowing full well the “idea” is doomed to fail.
What brand of windlass /motor is this?

[coopec43]

Originally Posted by Olly75

Thanks for the replies.

I epoxied the brushes back together because the motor maintenance manual from the manufacturer said thats what to do if the brushes were broken.....

I am very remote at the moment and i dread to think how long it would take to get a replacement motor. So will go with the rewind, but request the original size wire.

Puleeeeeze follow Jammer's and SkipperPete's advice!

I don't know why people have problems ordering items like carbon brushes online (Maybe Indonesia is on the list of banned countries?

[Jim Cate]

Indonesians have a politeness that extends to agreeing with oddball ideas from tourists to avoid offending them knowing full well the “idea” is doomed to fail.

Perhaps true, but the advice to epoxy came from the OEM, not the local chap.

And the usefulness of the fix depends a lot on the location of the fractures that are being glued: transverse or longitudinal for instance.

Jim

[coopec43]

Originally Posted by Jim Cate

Perhaps true, but the advice to epoxy came from the OEM, not the local chap.

And the usefulness of the fix depends a lot on the location of the fractures that are being glued: transverse or longitudinal for instance.

Jim

Jim

Why would you waste your time repairing something that costs thirty(?) dollars and has the potential to do expensive damage?

https://www.carbonoffroad.com.au/pro...eplacement-kit

[Jim Cate]

Originally Posted by coopec43

Jim

Why would you waste your time repairing something that costs thirty(?) dollars and has the potential to do expensive damage?

https://www.carbonoffroad.com.au/pro...eplacement-kit

Well, I've spent some time making repairs in remote places where delivery of anything is likely to be slow, expensive and often enough, unsuccessful. I've no idea how the OP's situation is relative to such concerns, but I can sympathize with the DIY approach.

I will admit to having modified carbon brushes to fit in non-original brush holders whilst in French Polynesia some years ago, and it was successful. But that was in a home-brew trolling generator, and not so highly stressed nor critical.

I'd be surprised if the repair chap who is skilled enough to rewind the rotor wouldn't also be able to DIY some new brushes, for he is doubtless far more competent than I!

Jim

[Jammer]

Originally Posted by Jim Cate

And the usefulness of the fix depends a lot on the location of the fractures that are being glued: transverse or longitudinal for instance.

There is a long list of things that I have successfully fixed with epoxy and also a long list of things that I have tried and failed to fix with epoxy.


I have, for example, flame-treated tired, old polyethylene tanks with cracks in them and fixed them with epoxy. I have tried and failed to fix the ABS dashboard bezel for a 2003 Chevrolet Suburban with epoxy. I have fixed circuit boards with JTAG debugging interfaces with epoxy. I have fixed jewelry with epoxy.


It has never occurred to me to try to fix a carbon brush with epoxy. Carbon brushes are readily available from many sources worldwide and can be shaped to meet the needs of a particular application with a file or sandpaper if the correct part is not readily available. They are wear items that require periodic replacement like an oil filter or a water pump impeller. From the OP it appears to me that the brushes were worn near or past their point of utility in any case. To try to epoxy a soft material that is supposed to be electrically conductive does not seem to me to be the best course of action though it is understandable if it is something that the manufacturer suggests.


For comic relief I offer this video of brush replacement on a 250 kw generator.

https://www.youtube.com/watch?v=5ojp3bxScGk

[RaymondR]

The stuff brushes are made from do not glue well.

[Olly75]

I should have said in my original post that the windlass originally failed about 120 miles from the nearest town and I had 90m of chain out!

The local guy has said that he will replace the bearings and brushes as standard. So its all good.

The brushes were cracked transversly and the lighthouse maintenance document definitely says they can be epoxied, so assume they know what they are doing.

[Bowdrie]

Originally Posted by Olly75

The brushes were cracked transversly and the lighthouse maintenance document definitely says they can be epoxied, so assume they know what they are doing.

My understanding is that Lighthouse uses a proprietary motor, not some repurposed "starter" motor?
Do you have any thoughts as to why the motor failed?
I ask that as I'm wondering how brushes could just crack, (perhaps defective, spring tension, etc.).
On a side note, have you been generally pleased with the features, construction, and operation of the Lighthouse?

[Olly75]

Originally Posted by Bowdrie

My understanding is that Lighthouse uses a proprietary motor, not some repurposed "starter" motor?
Do you have any thoughts as to why the motor failed?
I ask that as I'm wondering how brushes could just crack, (perhaps defective, spring tension, etc.).
On a side note, have you been generally pleased with the features, construction, and operation of the Lighthouse?

The lighthouse has been bullet proof to this point. It could happily pull a 40 kg anchor out of mud at 30 metres.The only gripe i have is part of the on deck housing rusts but understand they had a bad batch a few years ago.