SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jul 01, 2007, 06:53 AM
Registered User
North East England UK
Joined Jan 2003
1,432 Posts
Discussion
6 or 12 magnets

I'm embarking on making a 20mm* 10mm stator based motor to turn a 5*5 prop for my TT Velocity...

It has been suggested I use half of the usual number of magnets to up the kv of the motor...

Usually we shoot for 80% coverage of the flux ring?? so do I use 6 mags as suggested and ignore the 80% or do I use 12 mags in a NNSSNNSSNNSS config or some other suggestion?
Chippie is offline Find More Posts by Chippie
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 01, 2007, 07:57 AM
.
Joined Nov 2006
732 Posts
edited
prinz is offline Find More Posts by prinz
Last edited by prinz; Nov 10, 2008 at 01:23 PM.
Reply With Quote
Old Jul 01, 2007, 08:49 AM
Master of 1 point landing
Naperville, IL
Joined Jul 2005
2,841 Posts
Quote:
Originally Posted by Chippie
I'm embarking on making a 20mm* 10mm stator based motor to turn a 5*5 prop for my TT Velocity...

It has been suggested I use half of the usual number of magnets to up the kv of the motor...

Usually we shoot for 80% coverage of the flux ring?? so do I use 6 mags as suggested and ignore the 80% or do I use 12 mags in a NNSSNNSSNNSS config or some other suggestion?
what prinz says is sort of true. There is some efficient gains using NNSSNN in the GB motors Ive built. Additionally, the NSNSNS motor I have has some issues starting on my eflite esc - I have to use CC with a timing change.
ImaBiggles is offline Find More Posts by ImaBiggles
Reply With Quote
Old Jul 01, 2007, 11:30 AM
Registered User
stegla's Avatar
Guernsey
Joined Jan 2002
1,297 Posts
I'm using 12 magnets as 6 poles for high-revving EDF stuff and have found it much more efficient than 6 magnets.

Steve
stegla is offline Find More Posts by stegla
Reply With Quote
Old Jul 01, 2007, 12:04 PM
.
Joined Nov 2006
732 Posts
edited
prinz is offline Find More Posts by prinz
Last edited by prinz; Nov 10, 2008 at 01:23 PM.
Reply With Quote
Old Jul 01, 2007, 02:04 PM
jj1
Registered User
jj1's Avatar
Finland
Joined Oct 2004
234 Posts
CC, would like to see it too..
Once tested a 6 pole motor first with 6 mags then adding another set of 6 (NNSSNN...)
and keeping everything else the same. Didnt take exact measurements but IIRC the gain of the additional magnets was very small.
-JJ
jj1 is offline Find More Posts by jj1
Reply With Quote
Old Jul 01, 2007, 03:44 PM
Flying motor mount master
fly_boy99's Avatar
San Jose, California, United States
Joined Oct 2004
8,745 Posts
This is due to the two sets of magnets being put together being larger than the stator head. Which makes using single mags for 6 poles start easier. I've had much better results in using 6mags instead of 12 NNSS....

Again it depends on the width of your mags though...

Quote:
Originally Posted by ImaBiggles
what prinz says is sort of true. There is some efficient gains using NNSSNN in the GB motors Ive built. Additionally, the NSNSNS motor I have has some issues starting on my eflite esc - I have to use CC with a timing change.
fly_boy99 is offline Find More Posts by fly_boy99
Reply With Quote
Old Jul 01, 2007, 04:11 PM
Master of 1 point landing
Naperville, IL
Joined Jul 2005
2,841 Posts
I think it the thickness of the flux ring (rotor) also has a part to play in it. If your flux is skinny - extra mags may not help. If your flux it think (like the komodo) you might benefit from doubling up. Regardless, the gain is minimal and I really dont think it will a practicle dif UNLESS you are running a very heavy load.
ImaBiggles is offline Find More Posts by ImaBiggles
Reply With Quote
Old Jul 03, 2007, 01:21 PM
Registered User
stegla's Avatar
Guernsey
Joined Jan 2002
1,297 Posts
Quote:
Originally Posted by prinz
steve,
if you have hard data about your finding,
please post it.

PRINZ
Sorry............I made some other changes to the motors in question at the same time, namely, I changed from multiple strands of thin wire to a single thick wire.
So I have no real proof that NNSSNN gave me a leap in efficiency .

Steve
stegla is offline Find More Posts by stegla
Reply With Quote
Old Jul 04, 2007, 10:58 PM
Registered User
Ron H's Avatar
Bishopville S.C.
Joined May 2003
3,931 Posts
Quote:
Originally Posted by ImaBiggles
I think it the thickness of the flux ring (rotor) also has a part to play in it. If your flux is skinny - extra mags may not help. If your flux it think (like the komodo) you might benefit from doubling up. Regardless, the gain is minimal and I really dont think it will a practicle dif UNLESS you are running a very heavy load.
I think it is more due to the stator head v magnet width. I get good results when the magnets are the same or smaller than the heads, but see no improvement using pairs when one of the pair can reach one tooth while the other is still on the last one.

On a side note, a 20mm motor will run much cooler with 6 mags rather than 12, which means more watts can be used.
Ron H is online now Find More Posts by Ron H
Reply With Quote
Old Jul 06, 2007, 02:13 PM
Master of 1 point landing
Naperville, IL
Joined Jul 2005
2,841 Posts
Quote:
Originally Posted by Ron H

On a side note, a 20mm motor will run much cooler with 6 mags rather than 12, which means more watts can be used.
Why would you get an efficiency gain with 6 v 12 mags? If thats the case, they winner would be clear. Thats rather the opposite of what I saw on my GBv 12 v 6 may test (single stator 6 winds/22awg)
ImaBiggles is offline Find More Posts by ImaBiggles
Reply With Quote
Old Jul 06, 2007, 10:56 PM
Registered User
Ron H's Avatar
Bishopville S.C.
Joined May 2003
3,931 Posts
Cooler running motors can handle more watts in, because the magnets act as a fan and pull over the stator. A 20mm with 6 mags will have more air movement fom the can than a 12. The gain is all about gearing and letting the motor rev. The deadset DD guys will never get it.
Ron H is online now Find More Posts by Ron H
Reply With Quote
Old Jul 23, 2007, 08:02 AM
Registered User
stegla's Avatar
Guernsey
Joined Jan 2002
1,297 Posts
Just a thought?

Is it possible that , at high rpm, timing and switching from the ESC is made less critical by having NNSSNNSSNNSS instead of N S N S N S?

I'm still convinced that NNSSNNSSNNSS is the way to go for high speed and high power.

Steve
stegla is offline Find More Posts by stegla
Reply With Quote
Old Jul 23, 2007, 09:01 AM
Registered User
morphs's Avatar
UT
Joined Oct 2004
1,624 Posts
Quote:
Originally Posted by stegla
Just a thought?

Is it possible that , at high rpm, timing and switching from the ESC is made less critical by having NNSSNNSSNNSS instead of N S N S N S?

I'm still convinced that NNSSNNSSNNSS is the way to go for high speed and high power.

Steve

Have you ever tried 6 pole, 12 magnets with a delta wind?? I have and they were not good. The amp draw was through the roof and the motor got very hot.
morphs is offline Find More Posts by morphs
Reply With Quote
Old Jul 23, 2007, 03:02 PM
Registered User
stegla's Avatar
Guernsey
Joined Jan 2002
1,297 Posts
Quote:
Originally Posted by morphs
Have you ever tried 6 pole, 12 magnets with a delta wind?? I have and they were not good. The amp draw was through the roof and the motor got very hot.
Morphs
I have only had bad experiences with delta winds.

Today I've just finished a 20mm double with 8T of 22G 'Y' and NNSSNNSSNNSS curved magnets............sweet motor.......destined to go in a small wing.

Steve
stegla is offline Find More Posts by stegla
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Cool 6 Volt or 12 Volt Motor? DGoodrow Dock Talk 11 Jun 22, 2005 04:02 PM
CDROM 6 magnets or 12 bz1mcr Power Systems 38 May 26, 2005 09:57 PM
6 or 12 magnet poles cfischer505 Power Systems 2 Nov 17, 2004 08:31 PM
020 6 fet or 12 fet grr1941 Electric Plane Talk 2 May 27, 2002 04:57 PM
010 6 or 12 fet's grr1941 Electric Plane Talk 2 Dec 31, 2001 01:32 PM