# DIY BLDC design / construction



## simey_binker (May 13, 2009)

wow, you're ambitious. if you're in Toronto, I'd be willing to help. your location would be handy for recommending PM suppliers as well. I know some around me - just search a little.

I think the only thing I can help you on is cooling. it all depends on how you build it. how tight the motor is, and where it will be located. if it's a loose winding, and near the bottom of the vehicle, you may only need natural convection. if it's more tightly packed, look to using bendable copper tubing (used in plumbing) to potentially wrap the system for a water-jacket. all depends on how ambitious you are.

(watch out; electricity + water + fail = epic fail)

Sim


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## blank_rv-6a (Aug 17, 2009)

I'm brand new to this group but your post intrigues me. I too wish to make a BLDC motor that is powerful (at least 10HP 40HP prefered) and cheap. I have seen some magnet wire places out there that have everything pretty well covered including litz wire. I was thinking if you come up with a good design using standard copper then maybe you could go way off the deep end and gold plate some wire to truly give it that extra edge and have it worth the thousands of dollars the other guys are getting for their regular motors. As far as cooling I figure it doesn't need to be water in the copper pipe but more like transformer oil. That way if you spring a leak the motor/batt/controller is fine it's just the EPA looking at you. The RC guys are doing great things they just need to go a bit bigger. Let me know if you have a cool design and want to share. There's a TechShop in Portland that's got the CNC and rapid proto stuff for hackers like me.


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## simey_binker (May 13, 2009)

wow - its been a while since I've seen this thread. since I posted, I too have gotten into researching the potential of building a BLDC motor from scratch - one step at a time. there's another thread that discusses this further.

for those who have links to handy DIY BLDC motor stuff (ie: the RC plane world), could they send them along?

I'd be interested in how far the OP has gotten in his endeavors since he last posted. I think it would be neat to build one, and keep on improving it until it's decently competitive in price/performance. 

another thought is using the rare earth magnets in a Halbach Array configuration. not sure if this is commonly used, but it'd be neat to try it.

Sim

Sim


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## samborambo (Aug 27, 2008)

A more scientific approach to BLDC LRK design. http://myownhybrid.wordpress.com/

Might be useful.

Sam.


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## blank_rv-6a (Aug 17, 2009)

I think I found that thread so I will read it and see what happens. Here is one nice DIY motor for RC planes http://www.flyelectric.ukgateway.net/croc.htm always good to see some Halbach stuff out there. I found some for that aurora solar car with a cisro wheel motor. Whats the next step for magnets? The Batts are finaly going lead to lith to ???


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## the1cyrus (Aug 6, 2009)

blank_rv-6a said:


> I think I found that thread so I will read it and see what happens. Here is one nice DIY motor for RC planes http://www.flyelectric.ukgateway.net/croc.htm always good to see some Halbach stuff out there. I found some for that aurora solar car with a cisro wheel motor. Whats the next step for magnets? The Batts are finaly going lead to lith to ???


Yea this is a nice site. Looks like these motors have the stator in the middle and the outside is spinning. the designs ive seen had magnets in the middle and stators outside for the brushless design. guess it can be made different ways. 

don't you need some kind of special driver/controller for brushless dc motors? wish there was more info on that.

mtraven have you had any progress on making ur motor?


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## Amberwolf (May 29, 2009)

the1cyrus said:


> don't you need some kind of special driver/controller for brushless dc motors? wish there was more info on that.


Google for OSMC, the open-source motor controller, should have a lot of info on theirs, which is for RC planes and the like. Scale it up for bigger motors. 
________
Kaydence live


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## axbor22 (Jul 1, 2009)

Hi all!
Im working with the development of a 10kW motor intended for a Yamaha TZR 125 motorcycle conversion.
The motor is a: brushless double sided axial flux permanent magnet 3-phase AC aircore air cooled hall sensored delta conected motor with split stator option. Short and simple..... Enjoy!

http://www.youtube.com/watch?v=_TC57GCt37w
http://www.youtube.com/watch?v=hy6jZEW9uxc
http://www.youtube.com/watch?v=u0I0Tg8sxYw


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## Guest (Sep 14, 2009)

Does the metal shell of an electric motor ad anything to the magnetic feild in the windings? I mean if some one building an electric motor was to use aluminum or a mysterious but strong none conductive material to hold the motor together would it effect the out put of that motor?


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## samborambo (Aug 27, 2008)

notmrwizard said:


> Does the metal shell of an electric motor ad anything to the magnetic feild in the windings? I mean if some one building an electric motor was to use aluminum or a mysterious but strong none conductive material to hold the motor together would it effect the out put of that motor?


It affects the permeability of the magnetic circuit. An iron/steel backing to the rotor magnets has a higher permeability and therefore a lower reluctance (equivalent of electric resistance) in the magnetic circuit. That means you don't need such strong magnets to set up a field through a vast air gap.

For the stator windings, there's a field set up around the outside of the windings as well as the inside (but in the opposite direction). Any ferrous metal with low resistance near the outside of the windings will have an eddy current induced into it and may cause losses. Often, you find laminated steel stators with windings on every second tooth to make use of the external field of each winding.

You meantion Aluminium. Al is a strong, lightweight construction material but has low permeability (being non-ferrous) so it will hardly carry any flux. Use iron or steel for completing magnetic circuits with no alternating flux (ie: the backing of the permanent magnets) since there's no eddy current. If you want to increase the flux in the windings, instead of an air core use laminated silicon electrical steel (low eddy losses).

You may find this blog interesting and a good learning experience, at the least: http://myownhybrid.wordpress.com/2007/12/10/motor-design/

Sam.


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## samborambo (Aug 27, 2008)

axbor22 said:


> Hi all!
> Im working with the development of a 10kW motor intended for a Yamaha TZR 125 motorcycle conversion.
> The motor is a: brushless double sided axial flux permanent magnet 3-phase AC aircore air cooled hall sensored delta conected motor with split stator option. Short and simple..... Enjoy!
> 
> ...


axbor, looks excellent! keep up the good work


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