Extending Brushless Motor Leads

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Josh Hess
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Extending Brushless Motor Leads

Postby Josh Hess » Thu Sep 08, 2016 1:06 am

Working on my longboard project, I had to extend the three power leads from my motors. I thought this would be a fairly easy thing to do, however, it turned out to not be so easy. I found out that the leads were made up of twisted enamled copper wire (the same that the coils were made of) and this made soldering to them very difficult. If you are unfamiliar with soldering to enamled wire, you first have to scrape or sand off the the insulating coating. It is solvent resistant and burning it off will leave behind a black char that solder will not flow over. Normally with one or two strands of wire, sanding or scraping isn't so bad but since I had to do multiple motors with about ten strands in each lead, that would have taken forever.

I did a bit of research online and found that the only way to really get it off quickly is to dip it in a molten salt bath. For obvious reasons this will not be possible because it is uncommon to have a molten salt bath laying around. Other people on forums argued about solvents and how scraping removes copper so there wasn't a whole lot of good info online.

I decided to start playing with some things I had access to and I eventually found that the steel/tin wire brush attachment for a dremel works like a dream. I also found that a higher speed has a more desirable effect. Within two minutes, my motor had all of the strands stripped of enamel and soldering to them was easy as pie.

Here is a little step by step with pictures:

Cut leads leaving a bit to solder to:

Strip ends/remove old insulation:

Seperate/fan lead strands:

Use dremel to remove insulation (orient such that rotation pulls the wire)

Tin ends:

Strip and solder new leads:

Heat shrink:

That's it! I hope this guide was helpful!
Science may set limits to knowledge, but should not set limits to imagination.

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