Apr 08, 2004, 01:52 AM
Dismembered Member...

# One Hour CD ROM Construction Part 5

continued from here https://www.rcgroups.com/forums/show...5&pagenumber=1

 Apr 08, 2004, 03:41 AM MSDP Let's make CD ROM!!!! NOOOOO, CD ROM brushless motor!!! Thanks all for share. Jae-Kwang
Apr 08, 2004, 06:48 AM
Registered User
Quote:
 Originally posted by rysium Thanks Ron, You are the 'guru' so I though I'd better ask before I do something stupid. So I guess for my project (high torque DD) 24 magnets would give me more torque with about 5-6grams penalty. If I can get away with 12 magnets (for lighter and for cheaper motor), I will stick to it. However if I will not get my 20oz thrust I will have to addanother 12 magnets (6grams and 4 bucks more). I will let youi know the results. Richard
Why not try a 14-pole motor? I plan to do just that when my stators arrive. With 4mm wide and 1.5mm thick magnets.

Winding according to the table Ron posted should be: ACaBAbCBc

/Erik
 Apr 08, 2004, 07:49 AM Look what I did:D three doesnt divide into 14 too well. cant see how youll get more torque youll have magnets opposing a phase. right?
 Apr 08, 2004, 07:50 AM Registered User IŽll let Ron explain that. But as you can see a special winding is needed and yes, it does work. The LRK motors are either 14 pole too, FWIW. /Erik Last edited by Erik Johansson; Apr 08, 2004 at 08:00 AM.
 Apr 08, 2004, 08:37 AM Impossible? Hah! LRK are 14 magnet pole yes, but also 6 or 12 statorpoles. This makes the equation completely different.
Apr 08, 2004, 08:55 AM
Registered User
Quote:
 Originally posted by KreAture LRK are 14 magnet pole yes, but also 6 or 12 statorpoles. This makes the equation completely different.
Yes of course, I was just considering what he said about that 3 (phases) doesnŽt divide into 14 too well.

IŽm not getting into the technical discussion without more info so IŽll hope that Ron can explain this. I know he have discussed in in other threads and in the table he posted the 9 teeth / 14 pole combination was not marked as a "bad combination", so I trust that until itŽs proven wrong.

http://fast-results.com/lnl/nutpol.htm

/Erik
 Apr 08, 2004, 09:15 AM Registered User I just built a 14 pole motor and it definitely works. Now I am waiting on different batteries for more detailed results. So far I have tried it with 3 cells and it pulls 6.2 amps WOT with a GWS 10x6 HD. Want to try it with 2 cells and a SF prop. - Brian
 Apr 08, 2004, 10:01 AM Registered User The latest one I 've built turns a 10x6 DD at 2.9 amps. It has 12 -12 x 4 x1 magnets and doublestacked stator. The magnet spacing is to wide at only about 60% coverage.
 Apr 08, 2004, 10:03 AM Registered User This is quite addicting!
 Apr 08, 2004, 10:07 AM Registered User yep
Apr 08, 2004, 10:31 AM
Registered User

# Re: One Hour CD ROM Construction Part 5

Quote:
 Originally posted by arx_n_sparx couldn't find the wire, Tony, but this tubing looks interesting......
Go to page 715 of their online catalog. The magnet wire is at the bottom of the page.

Tony
Apr 08, 2004, 10:33 AM
homo ludens modellisticus
Quote:
 Originally posted by Erik Johansson IŽll let Ron explain that. But as you can see a special winding is needed and yes, it does work. The LRK motors are either 14 pole too, FWIW.
Guys, the table is not mine, it's from Ludwig Retzbach (the 'R' in lrk). It's all about pole/magnet overlap, which pole should attract and which pole should repel. If a coil attracts a magnet it will repel the magnet if you wind it the other way round.
Groeten Ron
Last edited by Ron van Sommeren; Apr 08, 2004 at 10:55 AM.
 Apr 08, 2004, 10:45 AM Registered User I found this on page 107 of the McMaster-Carr catalog: #50295K29 Metric Seamless Carbon Steel Tubing 12 mm OD, 9 mm ID, 1.5 mm Wall, 6' Length \$ 14.65 Each They have a range of metric sizes. I know very little about metallurgy, so would carbon steel tubing in short lengths be suitable for motor mounting? Tony Turley