Hub motor re-wire in 10 GA

[CanadianKid]

Hello im looking for the thinnest insulation for hub motor phase wires. I have 10 GA silicon insulated wire but they drag along the shaft and i cant seem to fit 3x. Whats the type of wire/insulation they normally use in BLDC. Couldnt find it anywhere. Thanks in advance

 

[spinningmagnets]

Look for Teflon insulated wire. Thin, tough, and resistant to high temps. Also called PTFE.

 

[amberwolf]

But keep in mind the Teflon is very easy to nick, cut, pinch, and damage, so it requires care in handling, and will need some form of jacket around it where it enters and leaves the axle, and wherever you tie it down, so it doesn't get cut by metal and short a phase or two or three to the axle, or each other.

It also doesn't age well; it will crack and fail over time. (may take more than a decade, or may take only a few years, depending on conditions and original quality).


The very thinnest insulation you can use (which is even more fragile than teflon) is to use the epoxy-coated magnet wire just like the motor windings. But it must be handled very carefully when passing it thru the axle, etc., though unlike teflon you can "patch" this by using the brush-on insulation repair liquids like Corona Dope.

I did a 10G rewire of my rightside MXUS 4503 some months back, using 10G solid wire out of a dead welder transformer, but they were too thick to put three thru the space I had even as just magnet wire, with no insulation jacket. I ended up having to use the thin cloth sleeves that came on certain parts of the welder internal wiring to cover where they went thru the axle to protect them from all the edges, and to groove my axle flats on both sides, both axle ends, so I could pass the wires between the bearing and the flats instead of thru the hole. One wire went on each side of the axle on one side, with the third wire out the other axle.

But others have done this just thru the axle holes succesfully (DoctorBass, IIRC, and others I don't remember).



For the wires you already have, you might try using a lubricant (water based, so it can't stay in there and eat away at anything plastic/etc).

 

[Punx0r]

Good news! Thanks to the desire of automotive OEMs to make their huge wiring harnesses as slim as possible, there exists ThinWall wire with durable "normal" insulation. I used such stuff on my last motor phase wire upgrade for the same reasons you've identified. I also bought silicone and teflon insulated wire and ended up not using it.

Example retailer, I'm sure you can find a local one: https://www.autoelectricsupplies.co.uk/product/70/category/114

 

[serious_sam]

I rewired my MXUS 3k V3 with 8AWG flexible silicone wire (like the turnigy stuff, but direct from Gina). I haven't heard of anyone getting wire that gauge in one of those motors. Probable that someone has, but I haven't heard. I figured I'd give it a go. I had to pull new wires anyway (mxus didn't install temp sensor, and they cut the sensor wire off inside), and I had the 8AWG available. I figured that if I couldn't get it to fit, i'd just keep removing bundles of strands and try again until it fit. But I managed to get the 8AWG through.

I stripped the silicone insulation, and used heatshrink around each phase, then put heatshrink around the 3 phases bundled with the hall/temp wires. So there are two layers of heatshrink between phases, and 2 layers between each phase and the axle. I used regular heatshrink, not the double thickness type with the glue layer. It's rated to 125degC, so lower than the original silicone insulation, but it should be ok. The flexibility of the wire helped to wrangle it through the axle. I used a dremel tool to ensure the axle hole was blended at the entry and exit, so less chance of cutting through the heatshrink. I ran a drill through the hole to ensure there were no dags or grooves that would catch on the heatshrink. I also added an additional couple of layers of heatshrink outside the axle for about 100mm, for added protection where it passes the inside edge of the disc, the disc screw heads, and where it bends and then gets zip tied to the bike frame.

I can't comment whether this will work long term, because I haven't finished the build yet (soon!). But I'm confident enough to risk my Nucular 12F.