Notices
Brushed/Brushless motors, speed controls, gear drives Discuss all aspects of brushless motors, brushed motors, speed controls (ESC's), gear drives and propellers in this forum.

Brushless delta or wye wound - how to tell?

Old 11-26-2009, 01:37 PM
  #1  
alaursen
Member
Thread Starter
 
Join Date: Nov 2009
Location: San Jose, CA
Posts: 40
Likes: 0
Received 0 Likes on 0 Posts
Default Brushless delta or wye wound - how to tell?

Hi All,

I am new to electric flight and learned that BL motor windingscan be either "delta" connected (like a triangle), or "wye" connected (like a star). Both have three phase leads of course. Here is the question. If I have a BL motor, how can I tell without asking the manufacturer or physically dismantling it and tracing the wiring? I did some resistance calculations for the theoreticalchange in DC resistance based on measuring across just two phase leads, then measuring with two of them shorted together. Guess what - my calcs show the exact same change in resistance for both types so I can't use this technique to determine how the windings are connected. I was thinking that I need to inject a pulse and see if it returns (using an oscilloscope) since the delta has "feedback" and the wye does not.

Anyone have a simpler way to do this?

Art
Old 12-06-2009, 07:55 PM
  #2  
coriolan
 
coriolan's Avatar
 
Join Date: Sep 2006
Location: Canada
Posts: 886
Received 0 Likes on 0 Posts
Default RE: Brushless delta or wye wound - how to tell?

Somewhere in that tread there must be an answer!
http://www.rcgroups.com/forums/showthread.php?t=587549
Old 12-07-2009, 10:18 PM
  #3  
mjsas
Member
 
Join Date: Nov 2007
Location: , MN
Posts: 36
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Brushless delta or wye wound - how to tell?

Actually there is no way to tell as they are equivalent. It would be the same as having two 50 ohm resistors in series or two 200 ohm resistors in parallel. Same o - same o.
Old 12-07-2009, 11:25 PM
  #4  
DaveFlynn
Senior Member
 
Join Date: Feb 2007
Location: Arcadia, CA
Posts: 450
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Brushless delta or wye wound - how to tell?

It's hard to tell, but there is a big difference when running the motor on DC, wye is better.
Old 12-08-2009, 01:24 AM
  #5  
jdetray
Senior Member
 
jdetray's Avatar
 
Join Date: Dec 2004
Location: Napoleon, OH
Posts: 1,617
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Brushless delta or wye wound - how to tell?


ORIGINAL: DaveFlynn

It's hard to tell, but there is a big difference when running the motor on DC, wye is better.
Hi Dave -

Could you explain your statement, please? I've built a bunch of brushless motors for R/C use, and while there may be good reasons to select either a Wye or Delta termination, I've never noted that one was always "better" than the other. Doesn't it depend on what you want the power system to do (big prop/small prop, torque/speed, direct drive/gearbox, etc.)?

As for how to determine the termination of a given motor, in some motors terminated as Wye, you can actually see a little stub where the three phases are connected together. Delta won't have that.

- Jeff
Old 12-08-2009, 02:53 AM
  #6  
DaveFlynn
Senior Member
 
Join Date: Feb 2007
Location: Arcadia, CA
Posts: 450
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Brushless delta or wye wound - how to tell?

Last summer I rewound a 4020 size motor and brought out all six ends. With the motor mounted to a digital torque wrench I measured the Kt and found the wye had a higher Kt than I expected and got more rpm per watt.
Old 12-09-2009, 06:54 PM
  #7  
alaursen
Member
Thread Starter
 
Join Date: Nov 2009
Location: San Jose, CA
Posts: 40
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Brushless delta or wye wound - how to tell?

Thanks Jeff,

I'll look for the wye stub you described.

There is a difference in low end torque and upper RPM between the two winding types. I believe the delta provides higher torque but lower maximum RPM and vice-versa for the wye (assuming the same numberof turns and poles of course).

Art

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.