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Old Dec 11, 2012, 01:54 PM
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8 magnets, 9 teeth. Hours of failure.

I have a motor that I burned up. The original wires were toast, and I couldn't see how it was before, but I would it ABaCAcBCb according to this chart. I chose the first occurence of the letter to be that phase's start wire and the last occurence of the letter to be the end. It just did not work at all. I wired it up delta I think. For starters, I'd like to know if I'm choosing the start and end windings correctly and any other advice is appreciated.
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Old Dec 11, 2012, 02:06 PM
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If you read the shown chart carefully , you will find AaABbBCcC for 9 slots and 8 magnets.
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Old Dec 11, 2012, 02:11 PM
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So...I'm stupid. For some reason, I was thinking a pole was a pair of magnets. But, I think today is the first time I've ever thought that. I'm sure on another day, I would have been smarter than that.
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Old Dec 12, 2012, 07:53 AM
Jack
USA, ME, Ellsworth
Joined May 2008
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Quote:
Originally Posted by maynardr6 View Post
I have a motor that I burned up. The original wires were toast, and I couldn't see how it was before, but I would it ABaCAcBCb according to this chart. I chose the first occurence of the letter to be that phase's start wire and the last occurence of the letter to be the end. It just did not work at all. I wired it up delta I think. For starters, I'd like to know if I'm choosing the start and end windings correctly and any other advice is appreciated.
That chart from the Motor Building Info page is good but there is a more recent version of it that used to be on the now defunct and missing powercroco and powerditto pages. That image is attached. If it is not clear, the number of arms or slots is horizontally across the top and the number of poles or magnets is vertically down the left side.

We recently found this replacement for the much beloved and also gone Winding Scheme Calculator or "bewicklungsrechner" that we used to have and use:

http://i.caendle.de/dev/test2/

If you go there and click in EN for English, enter 9 for Slots, 8 for Magnetpoles, D (or Y if you prefer) and click on Compute you will see the winding image for a 9N8P motor. I have done a screen shot of the image and attached it also.

Clicking on the Advanced mode will let you see the "AaABbBCcC" winding scheme, clicking on the Step by Step link will progress you through the arm by arm and phase by phase winding of the AaABbBCcC scheme.

That page is strong magic if that is not already apparent to you. It is relatively unexplained. But if you save that page as a type "web page. complete" (I do that from firefox) to a folder on your computer you will always have it and can run it offline too.

Jack
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Last edited by jackerbes; Dec 12, 2012 at 07:58 AM.
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Old Dec 12, 2012, 11:58 AM
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United States, MI, Ann Arbor
Joined Aug 2011
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Quote:
Originally Posted by maynardr6 View Post
I have a motor that I burned up. The original wires were toast, and I couldn't see how it was before, but I would it ABaCAcBCb according to this chart. I chose the first occurence of the letter to be that phase's start wire and the last occurence of the letter to be the end. It just did not work at all. I wired it up delta I think. For starters, I'd like to know if I'm choosing the start and end windings correctly and any other advice is appreciated.
9N8P is very common among servo motors. the winding for 9N8P, AaABbBCcC, can be done in a very interesting way. as shown here:
http://www.rcgroups.com/forums/showthread.php?t=1769209

by the way, ABaCAcBCb should also work, but the winding factor is too low.
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