Rewinding a 9C hub

I've gotten hold of a 9C hub motor that has suffered an unfortunate fate - its prior owner drilled cooling holes in it without removing the covers to do so - as such, the windings got drilled (ouch!).

Now, looking at the threads where people have rewound the turnigy RC motors etc, and this thread (http://www.endless-sphere.com/forums/viewtopic.php?f=30&t=25562) which outlines a winding scenario, its got me thinking that a nice heavy winding wire (like 1.5mm or so) would work well for a (very) slow wind motor for the trails - Maybe 14 or 15 turns, for low end RPM, probably wound single or paired like the BMC style geared motors (rather than heaps of little wires, I can see how that will end up).

Not sure where the hall sensors would sit in this winding scheme either, so sensorless is probably a must.

Gives an opportunity for delta/wye configuration as well. Other things like copper fill probably need to be thought through as well. At least the thicker wire holds its shape better.

Any assistance from someone who has attempted this would be great...

can't help on the rewinding directly, but for the halls, you could simply install them at literal 120 degree spacing around the stator, and they'd work pretty much no matter what winding scheme you use. This worked for my powerchair BLDC motor. Timing might be affected by where ont eh stator tooth you place the sensors, but if you have one of Burtie's Timing Adjusters, you can advance or retard the hall timing to fix that. (given your skills you could probably write/build one of your own, too. )

Farfle has rewound hubmotors (the dual MP) and so has Liveforphysics. Karma has done it too. I don't remember for sure who else has rewound hubs, but Thud and others have rewound many RC motors, which use the same principles.

If you get it figured out, show us how in detail. Preferably some video, and specs of the wire and where to get it.

I love the slow motors, and might run out of my stash of them someday. Really like my 2812 windings. I'm going to have to rewind one someday, got one burnt one already, so only one left now.

OK - I have removed the windings from the stator, and have wound 15 turns of 16 AWG (1.3mm) on a tooth to check for size - impressive copper fill (19.65mm2) but it is a major PITA to wind neatly. There is no way you could fit 15 turns of 1.6mm onto these teeth - maybe 10-11 tops (which would still be an excellent motor).

For those interested in the maths of the copper fill on these...

The original windings are usually ~60 turns of 0.6mm in each flavour - giving a total cross sectional area of 18.703 mm2. The 8X8 has the best fill at 19.950 mm2. Those Chinese kiddies winding these sure must have nimble fingers... My fat sausages are not so good at it though.

I'm going to build a 'third hand' with some scrap polyethelyene sheeting to do this too, easier on the hands.

Narrowed the wire down to either H class (200 degrees C) 1.3mmX1 or 1mmX2 going to get a kilo of it (I removed 430g of copper, for anyone who is interested). The insulation used will be Nomex 410 (H rated) IF I can find some at a decent price.

Trying to narrow down suppliers as well at this stage - there is a mob on Ebay (Brocotts - http://stores.ebay.com.au/Brocotts/) who have everything neccesary, which is good except for the price of shipping.

what winding pattern do you intend to use?

1. replicate the original distributed wind?
2. Concentrated wind?
3. LRK pattern?

personally i always fantasized about trying one using an LRK after reading about the DIY outrunners the RC boys have been doing.

rick

Photos please?

Winding scheme will be AaABbBbcCcaAabBbBCcCAaAabBbcCcaAaABbBCcCcaAabBbcCcC - pretty much what is already there. The weird pole/tooth combination makes it hard (51 teeth, 23 poles).

Photos attached as requested...

The original winding scheme - interesting...
View attachment 6

The position of the hall sensors - not sure if this is critical when in reference to the windings or only to the magnets - thoughs? :|


How to remove the windings - cut the 'loops' all on one side with good quality 'transistor nipper' style sidecutters...


And prise them loose.


And then you get this...
View attachment 3

And 430g of copper.


First (bad) attempt at winding 15 turns of 1.3mm H Class copper winding wire - pity the original insulation (DMD Poly mat/poly film/poly mat) is only rated for 150 degrees, this will have to go in favour for Nomex 410.

I believe Oakwright rewound a 9C. You might want to search his posts.

Unfortunatly it was a hall replacement and clean...

Frankly, I think I would just buy a replacement motor from Cell_Man, they are very reasonable.
You will have an interesting paper weight for your efforts.

Would if cellman supplied 12t muxus dd motors. 7t won't do for dirt riding.

15t, wow that's a slow motor even by my standards.

Details on where the wire comes from and such, when you get some with the right varnish on it.

So that piece of wire goes 15 times around the pole, then skips two spaces?

Got a 5304 that needs rewinding too. Be cool to ressurect it. I have tough hands, which would help.

dogman said:

Would if cellman supplied 12t muxus dd motors. 7t won't do for dirt riding.

15t, wow that's a slow motor even by my standards.

Details on where the wire comes from and such, when you get some with the right varnish on it.

So that piece of wire goes 15 times around the pole, then skips two spaces?

Got a 5304 that needs rewinding too. Be cool to ressurect it. I have tough hands, which would help.

Click to expand...

no, it goes 15 times around the first tooth and then 15 times in the opposite direction around the next tooth. reverse again for another 15 turns around that tooth. skip 6 teeth and repeat. 1st phase is easy, but later it gets to be real fun to try to keep the turns neat and tight will all of the slots almost completely full of copper.

did this once on a 5302 that i rewound for 5302/5304 series parallel and a couple of times for older Crystalyte 4012 motors.

rick