Neu - Y versus D windings

[VintageMA]

How to decide?

My question is in regards to BL motors with Y and D windings - specifically the Neus because they are the main brand I know to (aside from LMT) that make their motors available with both Y and D windings.

When you look on Neus motor page for the 15 series:
http://www.neumotors.com/20061222/1500_series_.html
you see that they have both a Y and a D winding version of each model and the D version seems to have a KV of ~1.77-1.78 times that of the Y.

But what does this really mean? Does it means that the Y windings are going to have more torque than the D windings?

Here's and example from another angle:
1515/2.5D = 1650 KV
1515/1.5Y = 1500 KV
Take the above two motors, the KVs are very close so in my mind ignore the difference in KV for this example. What is going to be the difference between two very similar motors one with a Y winding and one with a D? Will one have more torque than the other down low? Will one have better power at higher RPMs?

I'd really like to know because it would make the already tough decision process for picking a buggy/truck motor much easier.

Thx all.

[BrianG]

Here's a couple of threads that discuss this:

http://www.rc-monster.com/forum/showthread.php?t=5976

http://www.rc-monster.com/forum/showthread.php?t=6675

http://www.rc-monster.com/forum/showthread.php?t=7130

[VintageMA]

Thanks - tried a few searches but wasn't able to come up with much.

I wonder if anyone can directly answer the original question, comparing the two similar KV motors...

Too bad we can't try on the motors like you do shoes or something...would be nice to have the ideal fit as opposed to making whatever you buy work.

DM

[VintageMA]

I found this online:

"A motor with windings in delta configuration gives low torque at low rpm, but can give higher top rpm. Wye configuration gives high torque at low rpm, but not as high top rpm."

From this article: http://en.wikipedia.org/wiki/Brushle...electric_motor

And another one here: http://www.patentstorm.us/patents/64...scription.html

"Accordingly, in an application requiring high torque at a low speed, the motor is permanently configured in the wye configuration. Consequently, a conventional brushless motor design requires a compromise between high torque at a low speed and low torque at a high speed."

So..... my conclusion:
From the links BrianG provided and the articles above, there can be a comparison between Y and D for a given winding. But for a D and Y that come out with very close KV ratings, the difference is probably pretty negligible.

[BrianG]

@Vintage: I used the terms "wye" and "delta" for my search, so it came up with much more...

Based on the last post, it seems like it would be best to have the motors and ESC with 6 wire connections (a set for each coil) and the ESC could decide on the configuration depending on the speed the user is trying to attain. At slow speed, the ESC would configure as Y for max torque; at high speed, the ESC would reconfigure as delta. Wiring would be rather messy though, not to mention being a programming nightmare (from the firmware perspective)...

[VintageMA]

Originally Posted by BrianG

Based on the last post, it seems like it would be best to have the motors and ESC with 6 wire connections (a set for each coil) and the ESC could decide on the configuration depending on the speed the user is trying to attain. At slow speed, the ESC would configure as Y for max torque; at high speed, the ESC would reconfigure as delta. Wiring would be rather messy though, not to mention being a programming nightmare (from the firmware perspective)...

Not for nothing, but that is a totally awesome concept idea for essentially creating an automatic 2-speed e-transmission. No more of this I want high speed but will have to gear down to get torque and not overheat the motor, or I got a monster torque motor geared to the moon so I can get some speed out of it.

Neu / Castle - can you hear me?

[Peter Zicha]

Here is a very simplistic picture that gets to the point on how they are wired internally