Help with magnet wire selection

[Barncat]

I hope you know... no coating on the end where the carbon brush runs ;-)

Sent from my SM-G892A using Tapatalk

Yup, I got that. I did see a YouTuber spray paint the whole thing, then sand off the end. Seems it would be better to not paint the end and not have sandpaper near it, for fear of sanding too much coating off the wires. I think a gentle cleaning of the graphite off the contact area would suffice.

 

[RJSakowski]

The coating may just be a deposit of welding fumes over many years. The "smoke" is actually microfine particles. You see evidence of it in the viicinity of the weld after you weld. Debris from grinding us much heavier and falls to ground relatively quickly.

On the Variacs that I worked on recently, I first cleaned as much crud off the bare wiper area as I could using a piece of paper towel dampened with acetone and then a light sanding of the bare area with 600 grit wet or dry and a final wiping the dampened towel to remove any metallic dust. I use this process to clean up motor armatures as well.

 

[royesses]

Perhaps CRC electromotive cleaner would work. Available at many auto parts stores. Evaporates quickly and doesn't harm most coatings. I've used it on electronica and electric motor winding's with very good results.

Roy

 

[Barncat]

I got them all cleaned up with some alcohol. I had tested some on the old wire by submerging it in alcohol for about three days and it didn’t harm the coating. After disassembly I notice this on the bottom that rests on a piece of plastic. I assume this is why the one shorted out. I think it was just a lot of vibration over a long time wore off the coating. I plan on trying to find some non conductive epoxy or maybe potting compound to protect the end and then putting it back together. That sound like a good plan?
Thanks

 

[brino]

I would clean between windings very carefully first to make sure no conductive debris is in there.....

Then a coating of an insulator.
Non-conductive epoxy should work.
They do make spray-on coating for printed circuit boards, like these:
https://www.sparkfun.com/products/15882
https://www.amazon.com/MG-Chemicals...words=Conformal+Coating&qid=1604071997&sr=8-3

Also, be sure to add a spacer or otherwise change the mounting so that they cannot rub against anything!

Glad you found that before powering up!

-brino

 

[royesses]

Electric motor winding varnish:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Roy

 

[Barncat]

Electric motor winding varnish:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Roy

That seems like a good choice, but why doesn't it list copper as something it can used on?

 

[fixit]

I got them all cleaned up with some alcohol. I had tested some on the old wire by submerging it in alcohol for about three days and it didn’t harm the coating. After disassembly I notice this on the bottom that test on a piece of plastic. I assume this is why the one shorted out. I think it was just a lot of vibration over a long time wore off the coating. I plan on trying to find some non conductive epoxy or maybe potting compound to protect the end and then putting it back together. That sound like a good plan?
ThanksView attachment 342442

https://www.hisco.com/Brands/Glypta...ings/Paints-Primers/Enamel-Paints/1201A-21717

 

[Flyinfool]

That seems like a good choice, but why doesn't it list copper as something it can used on?

I do not think McM has copper as a material choice for descriptions. I looked at a number of produts that I am sure are great for copper and copper is never listed as an option. They only have room to list so many things.

 

[royesses]

That seems like a good choice, but why doesn't it list copper as something it can used on?

Seems strange, maybe because it includes brass and bronze? Most motors have copper or aluminum windings that I've seen. But it does say for motors so I would use it.

Roy