# Homemade BLDC motor From Ac Motor Stator



## Salty9 (Jul 13, 2009)

I don't know much about rewinding (At one time I though I did but got a book which convinced me that I didn't really want to rewind large AC motors). From my reading at:
http://www.rcgroups.com/electric-motor-design-and-construction-361/

3 phase motors want the number of stator teeth divisible by three. 

Magnet retention on an inrunner will be a problem also.


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## Arlo (Dec 27, 2009)

I have built this using a charging stator from a motorcycle. I will attach video of it running 8000 rpm I need to make it run at higher speeds so I have built a cast stator. Be very careful because the strength of the magnets and their speed vs the thickness of the lamination's will limit your top rpm and effect your core losses.
Dave one of the mods from this forum has a motor just like you describe.
You will find the controller will be the issue. It is not cheep to build or buy and will have to be really well designed for hi power levels.
I have a very awesome motor that I have been struggling with controllers on for 2 years. As well Dave has had controller issues with his!

http://www.youtube.com/watch?v=D8IGEb9DVCM


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## [email protected] (Apr 15, 2012)

Hey I am not building a Generator It is an Ev BLDC;I just want to know how to Rewind a 36Tooth Stator for my motor


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## [email protected] (Apr 15, 2012)

Hey I am not building a Generator It is an Ev BLDC;I just want to know how to Rewind a 36Tooth Stator for my motor


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## peggus (Feb 18, 2008)

Generator,motor, it's all the same. How you should wind it depends on many factors. I think you'll have better luck over at the LRK forums: http://groups.yahoo.com/group/lrk-torquemax/

They do this sort of things all the time.


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## Arlo (Dec 27, 2009)

[email protected] said:


> Hey I am not building a Generator It is an Ev BLDC;I just want to know how to Rewind a 3Tooth Stator for my motor


 If you watched my video you would see I made a motor not a generator.
Here is a link to help you with winding. http://powerditto.de/bewicklungsrechner.html


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## [email protected] (Apr 15, 2012)

Check The Stator and the rotor taken from a Ac Induction motor.......I was willing to get about 2 to 3 hp from this motor


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## [email protected] (Apr 15, 2012)

Please add up some suggestion


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## Arlo (Dec 27, 2009)

[email protected] said:


> Please add up some suggestion


 All you have to do it make a new rotor with magnets in it. When desigining your rotor see if you can machine it to hold the magnets realy well so centrifugal force cant rip them out. I have a special "Locktite Hysol" Thats a 2 part epoxy that is designed just for gluing magnets I will find a link if you like. whats the dimentions of the stator or rotor? Remember BLDC is the most power dense motor you can have so don't be suprrrised if it can make more power then you expect! And when ordering magnets make sure they are Hi temp rated, 80 degC will not cut it!


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## [email protected] (Apr 15, 2012)

Can any one please tell me how to wind a Y topology based 3 phase winding into my 36 tooth stator(INRUNNER)


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## Arlo (Dec 27, 2009)

[email protected] said:


> Can any one please tell me how to wind a Y topology based 3 phase winding into my 36 tooth stator(INRUNNER)


 WYE meens the end of each phase is conected together. 
Delta means the end of one connects to the start of one. http://www.google.ca/imgres?imgurl=...6U1qaGIApylvbYH&sqi=2&ved=0CFEQ9QEwAg&dur=300


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## [email protected] (Apr 15, 2012)

So tell me how do i Coil the stator;I know what do they means ;But in what sequence they are to be coiled if I am using Y wye topo


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## PStechPaul (May 1, 2012)

I am not too familiar with inrunner motors, but here is one that is good for at least 3 HP for only $50:
http://www.hobbyking.com/hobbyking/store/__4935__KB45_11XL_1000kv_Brushless_Inrunner.html

If you want to rewind the motor as a three phase AC induction motor, for lower voltage, with a 36 slot stator, I did that several years ago:










This was a 1/2 HP single phase 120 VAC PSC motor, and I rewound it as shown as a three phase 8 VAC 12 pole motor, which ran at about 600 RPM at 60 VAC but I overclocked it to 240 Hz for 2400 RPM. It is hard to see, but I used overlapping loops of wire so there were 18 bundles to get 12 poles (6 pole pairs x 3 phase). I was seeking lowest RPM and highest torque. If you want higher speed, you must use fewer poles. There are six wires total, and they can be connected either wye or delta for different voltages. The sequence of winding is not important as long as each winding in a phase goes the same way around each pole. To reverse the motor, just switch any two phases.

It seems like way too much work, and a high risk of failure, to attempt to build a BLDC motor from an induction motor. Why not just generate the three-phase AC and use a standard VF controller?

Here are some possibly helpful resources:
http://ww1.microchip.com/downloads/en/AppNotes/00885a.pdf
http://www.teslamotors.com/blog/induction-versus-dc-brushless-motors
http://www.uiitraining.com/b51a/100/15104ac_motor_rewind_intro1.htm
http://www.wisc-online.com/Objects/ViewObject.aspx?ID=IAU11808
http://www.freshpatents.com/Three-p...-winding-method-dt20060928ptan20060214529.php

HTH!


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## Ivansgarage (Sep 3, 2011)




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## mizlplix (May 1, 2011)

By using an in-runner design, you must make the magnet retention extremely strong. Or you will have to limit the top RPM, and that defeats your whole plan.

Most ultra high speed BLDC motors use an outrunner design. That way the magnets are inside the outer rotating shell and centrifugal force only seats the magnets more securely.

Your plan is sound and worth doing. Just keep thinking "magnet retention".....

Miz


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## [email protected] (Apr 15, 2012)

Smashed off the old wave Winding......Now have a look at the stator


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## [email protected] (Apr 15, 2012)

Yeah ;I know that the centrifugal force would through the magnets out of the shell so I would precisely consider the factor....


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## PStechPaul (May 1, 2012)

When I rewound my motor, I used the following sequence for 12 poles:

A C' B A' C B' ... x6

This was easier than having two layers as shown above for the four pole motor, but it runs slower (600 RPM at 60 Hz). However this allows it to be overclocked and thus may be able to provide 6 times the power at 360 Hz and 3600 RPM.


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## PStechPaul (May 1, 2012)

Arlo said:


> If you watched my video you would see I made a motor not a generator.
> Here is a link to help you with winding. http://powerditto.de/bewicklungsrechner.html


I'm not sure that I can agree with the winding schemes proposed by this utility. I understand that it is for an outrunner design, which I have no experience with, but as I understand it, the belts are not wound on individual pole pieces except in the case of 6 slots.

The belts surround several pole pieces, and sometimes have multiple layers with an overlap pattern that provides a smoothly varying phase shift of magnetism which reduces the cogging effect and makes for smoother operation.

In the illustration for 12 slots and two poles, for instance, there are two adjacent pole pieces, each of which has a clockwise winding of N turns. But in the slot between the pole pieces, there are 2N turns, but the current in them cancels, so there is zero net effect. You get the same effect by skipping that slot and winding around both poles.

But this is still very inefficient. In the slots between the poles, you have N windings at phase A, and also N windings at phase B, so the vector sum is actually 1/2 C'. It gets a bit confusing, and I don't claim to understand it fully, but if you examine commercial three phase motors (and also single phase) you will see overlapping belts.

Have you actually wound motors this way? It would be interesting to see if a different winding pattern would be more efficient. At the very least, it should reduce the overall length (and resistance) of the windings, and allow a heavier wire gauge.


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