Brushless motor winding class

[raptor347]

The pie wedge magnets had to be ground to shape before the were magnetized.

[donhuff]

But Brian, for the two winds to have the same kv. the DDD length of wire for ONE coil in the parallel set of three (let's call it 3 feet), will have to be the same length as it is for the Ds THREE coils wired in series (still 3 feet long).

The cross section has gotten small because now there are more turns hence fewer strands. Lets say that in our sample motor and with both winds having the same kv, a 2D will have 2 turns times three coils in series = 6 turns total. DDD will have 6 turns per coil, three coils in parallel, but still just 6 turns total. And the cross section should add together I would think, and end up about the same.

But like I said before, I'm not sure on any of this so tell me if I'm wrong and make me understand it, please. I guess I should wire a couple of stators with the two different winds, and measure them to see the difference. That wouldn't be to hard to do. But I don't even know how to measure resistance!!

[donhuff]

The pie wedge magnets had to be ground to shape before the were magnetized.

That makes sense.

I have made some 8 and 10 pole rotors for limited, and I had to grind the magnets a lot to get them to fit on the rotor hub.

[donhuff]

Darin,

In November 2019 the p-ltd mono saw record was 55 mph IIRC. 8 year old Will Schafer broke that @58 mph. Not really a big deal only 3 mph right. Then in December when it got NAMBA day the wind was blowing and waves were high. I'm not very good at going straight, (I hit the bank on my one and only try!) so I asked Martin Truex if he would drive it for me. I was able to do this because the water was so rough that even the big gas monos wouldn't run and I had the water to my self, and Martin was free to help me.

When I asked him to drive my little 29" boat he looked at me like I was some kind of an idiot. "That little boat in this water?" he chuckled and said "sure I'll drive anything". I told him that he shouldn't have to go past half throttle, and to just try to keep it right side up. I knew it would make it because it had gone 77+ mph at home and we still weren't full throttle!

Martin did a couple of short burst to get the feel for it, (he doesn't drive electric, nor does he drive monos) he called for the timer, READY? Ready they replied, and vroom vroom, and we had a new record. 60.2! Martin said he didn't think that he ever even got to half throttle. With Martin still driving and the water getting even rougher as the morning wore on, he was able to get the ltd mono 1/3 mile oval and the ltd offshore oval record. One of those was with my full sized 34" hull and a much milder motor.

Then this past November, again 9 year old Will Schafer broke Martin's ltd mono oval record. Again with a 34" racing hull and one of my motors.

So yes, they are really a lot stronger than stock. Setting the world on fire??? not sure, but if I ever get to hold the throttle on full Wabbit for a complete pass, I'm thinking 77-80 mph for a limited mono is FIRE breathing performance. This was with a 3656mm motor, my new 3760s are a good size step up in power.

[raptor347]

Don,
We're going to have to do some experimenting. My understanding, and I may be wrong, is that kV is related to the number of turns in each coil not the overall length of wire. We're building 9 electro magnets in each motor. I don't believe it maters if you power each coil independently (parallel DDD) in series (D wind), power up/down time is insignificant as you've said. Changing turn count for a coil changes the magnetic property of that coil. Like I said, I may be wrong, time to experiment.

[donhuff]

Well yes, your right by saying that the number of turns is what determines kv. BUT (and this is a big but) turn count also determines wire length!

I think what your not seeing is that the DDD wind, will HAVE to have a higher turn count, to have the same kv as a D wind.

Our sample motor for instance is a 2 D 6 pole 18 slot, we'll say that this gives us 2000 kv. To get the same kv using a DDD wind, you will have to go to 6 turns per coil. If you were to wind it a 2 DDD the kv would skyrocket!!! It would be something like three times the 2D kv.


Nobody ever talks about the length of the wire because it seems irreverent, but it's my (self taught) understanding that the length of the wire is what determines the turn count! You can't have one without the other.

Time "Insignificant" did I say that?? I'v said so much I have no idea anymore!


I think that the length of wire determines how much TIME it takes the Positive and the negative to collide and start working on the coils core, and then it takes a little more TIME to get the magnetic RISE and COLLAPSE of the coil. I find very little information on the subject, and the info I do find is way over my head. So, I'm basically talking out of my azz here.

[ray schrauwen]

Darin,

In November 2019 the p-ltd mono saw record was 55 mph IIRC. 8 year old Will Schafer broke that @58 mph. Not really a big deal only 3 mph right. Then in December when it got NAMBA day the wind was blowing and waves were high. I'm not very good at going straight, (I hit the bank on my one and only try!) so I asked Martin Truex if he would drive it for me. I was able to do this because the water was so rough that even the big gas monos wouldn't run and I had the water to my self, and Martin was free to help me.

When I asked him to drive my little 29" boat he looked at me like I was some kind of an idiot. "That little boat in this water?" he chuckled and said "sure I'll drive anything". I told him that he shouldn't have to go past half throttle, and to just try to keep it right side up. I knew it would make it because it had gone 77+ mph at home and we still weren't full throttle!

Martin did a couple of short burst to get the feel for it, (he doesn't drive electric, nor does he drive monos) he called for the timer, READY? Ready they replied, and vroom vroom, and we had a new record. 60.2! Martin said he didn't think that he ever even got to half throttle. With Martin still driving and the water getting even rougher as the morning wore on, he was able to get the ltd mono 1/3 mile oval and the ltd offshore oval record. One of those was with my full sized 34" hull and a much milder motor.

Then this past November, again 9 year old Will Schafer broke Martin's ltd mono oval record. Again with a 34" racing hull and one of my motors.

So yes, they are really a lot stronger than stock. Setting the world on fire??? not sure, but if I ever get to hold the throttle on full Wabbit for a complete pass, I'm thinking 77-80 mph for a limited mono is FIRE breathing performance. This was with a 3656mm motor, my new 3760s are a good size step up in power.

Wow! I'm curious as to what kind of prop you were using on that boat Don?

What are the 3760's??

[ray schrauwen]

The pie wedge magnets had to be ground to shape before the were magnetized.

Whoa... I was always curious what happens when you change a rotor to higher or lower number of poles and you guys are modifying rotors??!! Wholly cow man!

[donhuff]

Ray,

I was using an ABC 1717-17-45 on the SAW boat. The kv on that motor is 2550 I believe. For the oval I swapped to a 1714 to get the speed down some. Then the offshore boat had an 1814-17-45 prop, but it was a 2100 kv motor like we use for racing.

Both those motors were 6 poles. The jury is still out on whether increasing the pole count is really worth it or not. It's a lot of trouble to do it, and the ones that I have done aren't leaps and bounds stronger than the 6 pole they replace. They really seem to be about the same strength. I think that "crowding" the magnets against each other, is making one overlap it's neighbor a bit (magnetism wise) and killing off any benefit of having the extra magnet volume. Like a 6 cylinder and a V8 car engine, when the displacement of the two is the same, total achievable power is usually about the same.

And ya can't just add magnets, sometimes the stator has to change too. And this is all about the motors that I have worked with, so like going from a 6 pole to an 8. A 6 pole rotor can use a 9 or 18 slot stator, where an 8 or 10 pole can use a 3- 6 -9-12-15-18 slot stator.
And then you can't wind them all the same either. Some will need to be distributed and some concentrated, some will have to be wound AAA BBB CCC, some ABC ABC ABC, and then there's the Aab BCc Aab BCc, etc etc.

[ray schrauwen]

I’m quite impressed or in awe or both.

Thanks for the response. Hopefully I will get out more this summer to run and give one of your motors a try. The one I have is still virgin.

Take care an$ keep doing what you’re doing, it’s great.

[donhuff]

OOPS Ray,

I forgot to tell you what a 37x60 motor is. That's the maximum size allowed by the NAMBA rules.

[ray schrauwen]

Yeah, I figured that. Where did you get a motor with those dimensions? An outrunner?

[donhuff]

I didn't buy it with those dimensions, I had to make it have those dimensions.

[ray schrauwen]

ok, thanks