Re-winding a hubmotor

Electric Motors and Controllers
Post Reply
User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re-winding a hubmotor

Post by Farfle » Dec 19 2011 4:03pm

I just bit the bullet and ordered the stator stack for my next motor, and ill do the build-thread here. But first I have a few questions.

The gauge of wire in the motor is unknown, how do I tell what gauge it is, burn the insulation off or mic it or with the insulation?

The lam stack can be coated in a green epoxy of some sort to protect the windings from the sharp corners, what is that epoxy?

The glue holding the magnets on is unknown, would it be worth taking them off and re-gluing them with hysol or similar?

ill get pictures of the lam stack and magnet ring when I get it in the shop.
Test Review Revise Repeat

User avatar
bigmoose   100 MW

100 MW
Posts: 2653
Joined: Aug 06 2009 3:05pm
Location: North coast USA
Contact:

Re: Re-winding a hubmotor

Post by bigmoose » Dec 19 2011 9:10pm

The green epoxy is Scotchcast 263, I talked about it here: http://endless-sphere.com/forums/viewto ... st#p482141

The above post has a data sheet attached. The stuff is not that expensive (I talked with 3M), BUT it comes in 60 lb sacks and you have to buy 9 sacks! I found one reseller that would sell a single sack, but the price jumped to around $25 US/lb, so over a kilo buck for a sack.

If you use slot paper, use calendared Nomex 410 paper. If you need some of this let me know.

Measure the wire with insulation. Then burn it off and brillo pad the goop, and measure again.
"Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God..." all the best, Dave

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 21 2011 3:33pm

Thanks BM, don't have the donors in yet, but Ill be posting pictures ASAP. are there any alternatives to the scotchcast? i seriously considered JB weld, its heat resistant, flows well when warm, its cheap, plus, its slightly ferrous. What do you think?
Test Review Revise Repeat

User avatar
Thud   100 MW

100 MW
Posts: 2686
Joined: Aug 20 2009 6:20am
Location: West Michigan,USA

Re: Re-winding a hubmotor

Post by Thud » Dec 21 2011 3:40pm

Farfle,
IMHO you can side step the coating process completly if your using some nomex paper for insulation.
I am suprised by how easy it is to "pull a short" in the stock green epoxy on the turnigy motors....the nomex is indestructable & even more heat resistant than epoxy. just a light varnish on the stator to fight corosion is all you really need.

I even tried fiber glassing the ends of some rough stators trying to make them short proof...the paper is the bomb for its purpouse.
get some......

All information & advice provided by Thud are "Open Source" & free for personal use & distribution under the following agreement linked below.
http://creativecommons.org/licenses/by-nc-nd/3.0/

User avatar
bigmoose   100 MW

100 MW
Posts: 2653
Joined: Aug 06 2009 3:05pm
Location: North coast USA
Contact:

Re: Re-winding a hubmotor

Post by bigmoose » Dec 21 2011 8:48pm

I do have a formulation that I am working on to replace the unobtanium Scotchcast. I have the oven operational, and will have a test batch of the powder formulation in a few weeks. I need to make a miniature fluidized bed however to evenly coat the stator and see if we got it right or not.

I fully support Thuds statement on the use of calendared Nomex 410 paper. It is great stuff. I wanted to use the use calendared Nomex 410 paper over a good epoxy however for the extra protection. Regular brush on I do not believe will give the even coating. The Scotchast is done by heating the stator to a high temperature and then immersing it in a fluidized bed of the epoxy powder. It melts, it flows, it sets in less than a minute.
"Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God..." all the best, Dave

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 21 2011 10:13pm

Thanks so much for the help so far, will be getting some nomex paper then. but before that, more questions! so, what wire to use? something that's durable enough for a relative noob to pull (have re-wound countless CD-rom motors before brushless out runners were popular in RC) but still having a good temperature resistance. And one more thing. Its all hypothetical, but assuming the motor is wound with 4 turns of 4 strands of 23guage, I want to double the KV of the motor, and I am taking the lam stack and making it twice as wide, does that mean that it has to be wound with 1 turn of 16 paralleled strands to achieve that? and how the farck would I do that? because one turn of an equivalent gauge single wire, or pair of wires probably wont fit in the slot, and 16 paralleled wires would be a serious handful. Thanks again with the help so far.
Test Review Revise Repeat

User avatar
fechter   100 GW

100 GW
Posts: 13185
Joined: Dec 31 2006 3:23pm
Location: California Bay Area, USA

Re: Re-winding a hubmotor

Post by fechter » Dec 21 2011 11:26pm

I can vouch for the Nomex paper too. Really tough stuff. Another thing that helps is to sand off the razor sharp corners on the laminations. I don't think they debur them after punching them out. Just enough so it doesn't feel sharp. There will be far less chance of punching through if the edges are rounded.

Multi-filar windings can have some advantages but also have some challenges. For a rewind, I'd generally stay close to what the original configuration was.

I used some nasty varnish stuff on one of mine to prevent the windings from vibrating. I susupect there is a better product for that. It did work though.
"One test is worth a thousand opinions"

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 27 2011 12:57pm

Woo! New motors are here :D , ill get pictures of their internals as soon as I can get them apart.
Test Review Revise Repeat

User avatar
Arlo1   100 GW

100 GW
Posts: 8176
Joined: Apr 26 2009 10:36pm
Location: Nanaimo
Contact:

Re: Re-winding a hubmotor

Post by Arlo1 » Dec 27 2011 1:16pm

This is exciting! Use leather gloves to wind with. And eat your spinach :wink:
My Leaf motor controller build. http://endless-sphere.com/forums/viewto ... 27#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
Support me on Patreon. https://www.patreon.com/user/posts?u=6842045
http://www.undergroundelectrics.ca/

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 27 2011 2:15pm

ooh yeah, winding CDrom motors with 28ga wire is probably a joke compared to this.
Test Review Revise Repeat

User avatar
Thud   100 MW

100 MW
Posts: 2686
Joined: Aug 20 2009 6:20am
Location: West Michigan,USA

Re: Re-winding a hubmotor

Post by Thud » Dec 27 2011 2:21pm

baaaa. how hard can it be? :twisted: :twisted:

I wind tunigys bare-handed these days as i have caloused up signifigantly pulling 14 & 12g wire for more than a few guys on the board.
but I still HATE winding anything with more than 2 strands.

we looking at 30+ teeth here Farfle? (i'll be happy to watch this one from the side lines LOL)
hubzilla is born......or is that frankenhub?
get some......

All information & advice provided by Thud are "Open Source" & free for personal use & distribution under the following agreement linked below.
http://creativecommons.org/licenses/by-nc-nd/3.0/

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 27 2011 2:35pm

This will send Hubzilla home. Not sure what its going to be named, but its 63 teeth. Im thinking a name something along the lines of PITA :lol:
Test Review Revise Repeat

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 27 2011 4:09pm

woo! have pictures, the stators weren't as wide as Id hoped, so I may end up doing three of them, but will see what it looks like with two.

Image

Image

Image

Image

looks like it will be 38mm wide, and 260mm in diameter, with 63 teeth and 56 magnets.
Test Review Revise Repeat

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 27 2011 4:55pm

just cut one of the coils, and it looks like its 6 turns of 8 wires, as there is 48 wires passing thru one slot. Is this correct?
Test Review Revise Repeat

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 28 2011 3:12am

Got the windings cut off and machined the stator cores to mate flush with eachother. But when i was machining the magnet ring to be flush to the magnets I effed up, hopefully not too badly. I lathed the very edge of the magnet ring a little tiny bit which fractured the edges of the magnets. None of them are cracked, and a non-cracked magnet ring will be right next to it, if all else fails i can buy new magnets, as they are just flat magnets and not any special curve.

Image
Image
Image
Test Review Revise Repeat

User avatar
fechter   100 GW

100 GW
Posts: 13185
Joined: Dec 31 2006 3:23pm
Location: California Bay Area, USA

Re: Re-winding a hubmotor

Post by fechter » Dec 28 2011 11:48am

The magnet chipping is not a real show stopper. I wouldn't worry about it other than you should paint or epoxy over the exposed magnet material. The tiny decrease in magnetic strength will slightly change the voltage constant but probably not enough to measure.
"One test is worth a thousand opinions"

User avatar
Arlo1   100 GW

100 GW
Posts: 8176
Joined: Apr 26 2009 10:36pm
Location: Nanaimo
Contact:

Re: Re-winding a hubmotor

Post by Arlo1 » Dec 28 2011 12:20pm

Farfle wrote:Got the windings cut off and machined the stator cores to mate flush with eachother. But when i was machining the magnet ring to be flush to the magnets I effed up, hopefully not too badly. I lathed the very edge of the magnet ring a little tiny bit which fractured the edges of the magnets. None of them are cracked, and a non-cracked magnet ring will be right next to it, if all else fails i can buy new magnets, as they are just flat magnets and not any special curve.

Image
I bet the magnets chiped when the stator was installed into the magnet ring last. To many people are not carefull enough with that.
My Leaf motor controller build. http://endless-sphere.com/forums/viewto ... 27#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
Support me on Patreon. https://www.patreon.com/user/posts?u=6842045
http://www.undergroundelectrics.ca/

User avatar
Gordo   100 kW

100 kW
Posts: 1218
Joined: May 23 2010 4:46pm
Location: THE COLD WHITE NORTHWEST, EH?

Re: Re-winding a hubmotor

Post by Gordo » Dec 28 2011 12:22pm

If you want to see what effect the chips in the magnet have, put a sheet of white paper over the magnets and sprinkle some iron filings on. Tap the paper slightly and you will see the lines of flux. I don't think you will see a huge difference between the chipped ones and the perfect ones.
X-treme 3KW Scooter...OFF ROAD ONLY....Giant 1KW 48V 24" Hubmotor....E-Apex 1KW 48V 26" Hubmotor, built 2012-05-26
Thanks Justin, for saving ES. May Grin Tech grow and prosper.

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 28 2011 12:28pm

Arlo, they chipped when I tried mashing into them with the toolholder at 860 rpm while i was machining the sideplate. If any of you get to machine magnets, i would highly reccoment high speed steel, as it produces a spectacular magnesium-like fireworks show.
Test Review Revise Repeat

User avatar
Arlo1   100 GW

100 GW
Posts: 8176
Joined: Apr 26 2009 10:36pm
Location: Nanaimo
Contact:

Re: Re-winding a hubmotor

Post by Arlo1 » Dec 28 2011 12:32pm

Farfle wrote:Arlo, they chipped when I tried mashing into them with the toolholder at 860 rpm while i was machining the sideplate. If any of you get to machine magnets, i would highly reccoment high speed steel, as it produces a spectacular magnesium-like fireworks show.
lol sweet.
My Leaf motor controller build. http://endless-sphere.com/forums/viewto ... 27#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
Support me on Patreon. https://www.patreon.com/user/posts?u=6842045
http://www.undergroundelectrics.ca/

User avatar
parabellum   10 MW

10 MW
Posts: 2057
Joined: Nov 19 2010 9:55am
Location: Dominican Republic, north.

Re: Re-winding a hubmotor

Post by parabellum » Dec 28 2011 2:10pm

Farfle wrote:just cut one of the coils, and it looks like its 6 turns of 8 wires, as there is 48 wires passing thru one slot. Is this correct?
No, actually they are 96 wires thru one slot if you count the other coil. :D
Is it some kind of known motors you use, or is it something new?

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 28 2011 3:06pm

parabellum wrote:
Farfle wrote:just cut one of the coils, and it looks like its 6 turns of 8 wires, as there is 48 wires passing thru one slot. Is this correct?
No, actually they are 96 wires thru one slot if you count the other coil. :D
Is it some kind of known motors you use, or is it something new?
Correct sorry, yes 96 per slot. And it is a known motor, its a magic pie hubmotor :D
Test Review Revise Repeat

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 28 2011 5:41pm

Ok, the existing wire mics out to be .55-.51mm with burned-off varnish and .61mm with varnish. What guage wire is it?

Image

Image
Test Review Revise Repeat

rebelpilot   1 kW

1 kW
Posts: 317
Joined: Jul 28 2010 12:44pm
Location: Ontario, Canada

Re: Re-winding a hubmotor

Post by rebelpilot » Dec 28 2011 5:49pm

Farfle wrote:Ok, the existing wire mics out to be .55-.51mm with burned-off varnish and .61mm with varnish. What guage wire is it?
24 gauge AWG I think.
http://www.tnt-audio.com/clinica/awg_e.html

User avatar
Farfle   1 MW

1 MW
Posts: 1754
Joined: Jun 27 2010 10:42am
Location: Redmond OR

Re: Re-winding a hubmotor

Post by Farfle » Dec 28 2011 9:26pm

More progress made, I think Doctorbass would be proud :D . I got the two magnet rings glued together with DP420, Thats a B*$&# by the way. They do NOT want to be side by side, ended up machining a massive plywood plug that gets pressed into both rings, screwed it and the bottom ring to the table and stacked the two, and held them together with vise-grips. Hopefully it comes out tomorrow when the glue dries :shock: . Oh and heres some side-by-side comparisons with an old crystalyte outer case:

Image

Image

Image

Image
Test Review Revise Repeat

Post Reply