Aug 26, 2011, 04:53 PM

South Africa, GP, Pretoria
Joined Jul 2003
422 Posts
Quote:
 Originally Posted by Ron van Sommeren I have not played that much with it. The tool (advanced) gives some numbers, I don't understand all of them though. Maybe you can figure out their meaning?
Hi Ron

I'm glad you mentioned the improved winding diagram 'calculator' again. That prompted me to have another look at it.

It gives a number that's called "winding factor". I'm not sure what this means, but by clicking on "advanced", one can input values like "stator diameter", "slot opening" and interestingly, the amount of "skewing". By ticking the "into the table" tickbox, it recalculates the mysterious "winding factor" value.

From what I've seen, the advanced function could be very handy for verifying LRK design layout, because the "winding factor" bars in the graph are high only for the "legal" magnet pole numbers if number of slots and poles comply with the LRK rules. I like this new tool !!

Also, the higher the skewing number, the lower the "winding factor" number. I wish someone would explain what it means.

Christo
Aug 26, 2011, 05:03 PM
Registered User
Antony (France)
Joined Sep 2003
3,127 Posts
Quote:
 Originally Posted by Skylar Hi Louis You mentioned some valid points. a) Phase relationship. So a poorly constructed/designed motor with varying stator teeth width or irregular magnet spacing could still work well as a generator. Very interesting. Christo
Hi Christo
If you rectify for DC use (to load a battery) ..
phase relation-ship is not important
(for example if you have 0, 60 deg, 120 deg instead of 0, -120 deg, 120 deg
it is not important for a generator)

BUT amplitude of BEMF (V/rpm) is important
So a bad design or an error on the phases windings in serial is not a good thing. And there is a "merit factor" for every configuration.
I have the simulation software (my secret !!) to analyze that (copper distribution and magnets distribution)

dLRK or LRK are very close together (as for merit factor)
Louis
Aug 26, 2011, 07:50 PM
homo ludens modellisticus
Netherlands, GE, Nijmegen
Joined Feb 2001
11,618 Posts
Quote:
 Originally Posted by Skylar ... I wish someone would explain what it means.
On that page you'll find that Felix Niessen is the author. The link points to his company website.

Prettig weekend Ron
diy motor tipsDrive Calculator
diy motor groupCumulus MFC
 Aug 26, 2011, 11:36 PM Registered User Joined Sep 2010 104 Posts I found this: http://www.emetor.com/manual/glossary/winding-factor/ Don't make sense to me. But I bet it does for you guys.
Aug 27, 2011, 03:39 AM
Registered User
Antony (France)
Joined Sep 2003
3,127 Posts
Quote:
 Originally Posted by modisc Designing a motor is a very sophisticated work. Simply try wiring on commercially purchased, or "hardware" fixed models, is a good start anyway. Im not specialized in this area, actually, my profession is not even close to RC. But to me, motors are just like human body, a lot to explore and a lot to think, yet a lot to fix.
Hi Modisc
I agree with your posts #24 and #25
12N8P is also a very good config, however there are some "distorsions" BEMF waveform (some speaks about harmonics).
I am a fan of Fourier analysis but in this case I prefer to think in the time domain and the Lorentz forces when rotor is rotating in regard of current conductors distribution.
I have to add that there is a lot to do in ESC algorithms to get the best time instants to commute phase sub cycles. Also a sophisticated task.
Louis
Aug 27, 2011, 04:10 AM

South Africa, GP, Pretoria
Joined Jul 2003
422 Posts
Quote:
 Originally Posted by BoomStriker
Hi BoomStriker

Thanks for the link. That website is very informative and useful, especially the online motor design program Emetor.

Christo
Aug 27, 2011, 05:03 AM
Registered User
Antony (France)
Joined Sep 2003
3,127 Posts
Quote:
 Originally Posted by Skylar Hi BoomStriker Thanks for the link. That website is very informative and useful, especially the online motor design program Emetor. Christo
Hi Christo
Did you succeed to input all parameters without one "error"
If yes what are all your data ? (file ?)
Louis
 Aug 27, 2011, 05:18 AM 我爱飞行 . . . I love flying South Africa, GP, Pretoria Joined Jul 2003 422 Posts Hi Louis At first I kept on getting a "Tooth width is too large - error", then I changed to "Concentrated winding" and it worked without any errors. Apparently, "Distributed winding" means something different to them. If you still don't succeed, let me know and I'll e-mail you my file. Christo
 Aug 27, 2011, 05:29 AM 我爱飞行 . . . I love flying South Africa, GP, Pretoria Joined Jul 2003 422 Posts Emetor Louis Once you've selected "Concentrated winding", "2 layers" means dLRK and "1 layer" is LRK. Christo
 Aug 27, 2011, 06:01 AM Jack USA, ME, Ellsworth Joined May 2008 17,703 Posts This is a step backwards from the level of the conversation here but I finally figured out what "SPS" stands for, "..Lucas, Retzbach and Kühfuss (LRK) motors, also known as Split Phase Sector (SPS) motors..." http://www.femm.info/wiki/LRKAnalysis That is a pretty attractive set of pages there. Jack
Aug 27, 2011, 06:44 AM

South Africa, GP, Pretoria
Joined Jul 2003
422 Posts
Quote:
 Originally Posted by jackerbes ... I finally figured out what "SPS" stands for.
Jack

I've added the meaning of SPS to the first post - for the benefit of new readers of this thread. Thanks for pointing this out.

Christo
 Aug 27, 2011, 06:56 AM 我爱飞行 . . . I love flying South Africa, GP, Pretoria Joined Jul 2003 422 Posts The origin of SPS (LRK) I think that it's very fitting to mention here where the SPS (LRK) winding scheme comes from. We know LRK stands for Lucas, Retzbach and Kühfuss, the 3 guys who popularized the outrunner motor as we know it. In this post Christian Lucas gives credit to Zelinski and Schoep from Poland who used it in big, slow-running alternators powered by water or windmills. Christo
Aug 27, 2011, 08:00 AM
Inspiration
United States, MI, Ann Arbor
Joined Aug 2011
890 Posts
Quote:
 Originally Posted by Fourdan Hi Modisc I agree with your posts #24 and #25 12N8P is also a very good config, however there are some "distorsions" BEMF waveform (some speaks about harmonics). Louis
I assume there will be more distortions in 12N4P and 12N2P? How about 12N16P?
Aug 27, 2011, 09:21 AM
Registered User
Antony (France)
Joined Sep 2003
3,127 Posts
Quote:
 Originally Posted by modisc I assume there will be more distortions in 12N4P and 12N2P? How about 12N16P?
Hi
Yes more distorsions in 12N2P and 12N4P
12N16P is OK (low distorsion) but the "merit factor" is less
My favourite is 12N10P (for the same magnet coverage %; could be 80-90%)
Louis
Aug 27, 2011, 09:52 AM
Inspiration
United States, MI, Ann Arbor
Joined Aug 2011
890 Posts
Quote:
 Originally Posted by Fourdan Hi Yes more distorsions in 12N2P and 12N4P 12N16P is OK (low distorsion) but the "merit factor" is less My favourite is 12N10P (for the same magnet coverage %; could be 80-90%) Louis
I just posted a thread about winding factors. Please see whether that term can actually solve some problems