Direct Drive to Diff E Revo Build

sikeston34m,
Do you have any interference problems using the 27mhz am radio gear? Very nice work too by the way.

[sikeston34m]

Originally Posted by Desmo

sikeston34m,
Do you have any interference problems using the 27mhz am radio gear? Very nice work too by the way.

Thanks Desmo.

No Interference Problems at all so far.

[johnrobholmes]

Give the 16awg a shot, it should be a lot easier. Are you using any winding tools? I whittled two chopsticks flat for smashing and pushing the winds in, then I have two flat sticks that keep the winds tight while I move around to the other side. The ends aren't as important as the fill between the slots.

Got any data on the CSA of 5 strands of 22awg? My figure shows .002531153, which is still less than 14awg. Looks like we need to find some 15.5 or 15awg wire.

[sikeston34m]

Originally Posted by johnrobholmes

Give the 16awg a shot, it should be a lot easier. Are you using any winding tools? I whittled two chopsticks flat for smashing and pushing the winds in, then I have two flat sticks that keep the winds tight while I move around to the other side. The ends aren't as important as the fill between the slots.

Got any data on the CSA of 5 strands of 22awg? My figure shows .002531153, which is still less than 14awg. Looks like we need to find some 15.5 or 15awg wire.

I'm going to be making some winding tools. In practicing, I was using a small screw driver and some needle nose pliers that have teeth in the jaws. That don't work. It's way too easy to create tears in the wire coating.

Something I've noticed about making the decision on just how large the wire can be, We need two wires to lay side by side in the lower valley of the poles. Like the Scorpion 3032 that the Croco guy wound. While reading the website through a German translator, he calls it an 8wd with 1.0mm wire. According to him, This is a 550kv wind, but tests from person to person are inconsistent. This test was probably done with a working load of who knows what.

1mm wire is 18awg. Take a close look at this picture. If too large a wire is used, the bending radius won't be tight enough at the ends either.


Each size of stator is different with how much of what size wire will fit.

I'm really thinking about getting another AXI 4120 motor to rewind. The more I think about the custom 4130, the more I feel like I'm going to have a motor that is going to draw so many amps, the Quark 125amp Monster Pro won't even be enough on 4S Lipo. Aside from this, trying to figure how many kv it will be is a guess at best, since there isn't a 600kv to 700kv currently on the market to compare this to. I think the amp draw would be out the roof, so would performance, but this is why motor builders move up to High Voltage to get more performance. It's all about keeping the amp draw manageable.

Top speed is great with the 4120/14 on 4S. Being 660kv, it's much easier to come up with a wye wind that will be the same kv and draw close to the same amperage.

"Got any data on the CSA of 5 strands of 22awg? My figure shows .002531153, which is still less than 14awg."

I quickly figured the Single Strand CSA of the current Scorpion offerings for the 3032. Check this out.

3032-8 988kv 27 strand 8 turn 30 awg .0000785 x 27 = Single Strand CSA = .0021195 Total CSA is .0021195 x 8 = .016956
3032-10 823kv 24 strand 10 turn 30 awg .0000785 x 24 = Single Strand CSA = .001884 Total CSA is .001884 x 10 = .01884
3032-12 687kv 20 strand 12 turn 30 awg .0000785 x 20 = Single Strand CSA = .00157 Total CSA is .00157 x 12 = .01884

5 Strands of 22awg is a CSA of .002532253
4 Strands of 22awg is a CSA of .0020258024

It's easy to figure Total Cross Section Area.

Single Strand CSA x Number of turns = Total CSA

The Greater the Total CSA, the higher the amp carrying ability, the more power it will make AND the more efficient the motor will be.

With the 3032, shoot for a Total CSA of .01884 or better.

The German guy's Croco motor wound with 18awg has a Total CSA of .010048

This tells me the Scorpion Factory winds are more efficient and make more power than the Croco motor.

I think I will get some short samples of each awg wire and see how many strands of what will fit the best and work the best according to the figures.

The 4120 winding should be easy enough to convert to a 660kv Wye wind and should tell us what we want to know. I think I'll shoot for that.

[johnrobholmes]

It IS very difficult to determine what the KV will be before winding, although basing it from similar sized stators and magnet strengths does help. The hardest part is that every stator fill is different. I don't think I can have any more wire pushed into my stator, the 5 strands of 22awg is such a tight fit I have to thread some of the last winds in.


I kinda eyeballed the fit of my wire. Put in a chunk of strands and said "that looks enough". My math was that 40 strands would barely fit.

[sikeston34m]

Originally Posted by johnrobholmes

It IS very difficult to determine what the KV will be before winding, although basing it from similar sized stators and magnet strengths does help. The hardest part is that every stator fill is different. I don't think I can have any more wire pushed into my stator, the 5 strands of 22awg is such a tight fit I have to thread some of the last winds in.


I kinda eyeballed the fit of my wire. Put in a chunk of strands and said "that looks enough". My math was that 40 strands would barely fit.

That's an 8 turn motor?

An 8 turn factory motor is 988kv. Your motor's amp carrying ability should be better with a Total CSA of .020258024

Good Job! You beat the factory on fill.

[aqwut]

Originally Posted by sikeston34m

That's an 8 turn motor?

An 8 turn factory motor is 988kv. Your motor's amp carrying ability should be better with a Total CSA of .020258024

Good Job! You beat the factory on fill.

Maybe off topic.. Lehner won't fix my 2280.. you guys know how to rewind inrunners?.. my 2280 needs a new can or to be rewound..

[johnrobholmes]

Originally Posted by sikeston34m

That's an 8 turn motor?

An 8 turn factory motor is 988kv. Your motor's amp carrying ability should be better with a Total CSA of .020258024

Good Job! You beat the factory on fill.

Yeah, I went with an 8 turn so I could compare it to the 8 turn Wye I have from the factory. I still haven't finished the last phase, another 1.5 hours of winding.


If you want to get a ballpark for kv, a motor that is twice as long with the same wind count will have half the kv. Same formula works for a motor that is 1.5 times as long. As for wind count, the formula is really stinkin complicated so I'm not going to even attempt. When you change stator diameter it messes with things. When you change magnet strength it messes with things too.

[johnrobholmes]

Lehner is slotless if I remember. You need a winding jig and press for that, those are compressed and baked windings.

[MTBikerTim]

That is really cool. Nice work. Do you balance the rotor or anything?

[sikeston34m]

Originally Posted by MTBikerTim

That is really cool. Nice work. Do you balance the rotor or anything?

Since I just rewound it, the factory Rotating Endbell was already balanced.

The Stator part is stationary. It doesn't turn.

[zeropointbug]

Originally Posted by sikeston34m

Since I just rewound it, the factory Rotating Endbell was already balanced.

The Stator part is stationary. It doesn't turn.

Precisely. And nice work Sike! Makes me want to get another project going for a slotless/halbach array Bl motor... they have up to 98% efficiency these things!

[sikeston34m]

Originally Posted by zeropointbug

Precisely. And nice work Sike! Makes me want to get another project going for a slotless/halbach array Bl motor... they have up to 98% efficiency these things!

Thanks ZPB. How's your Revo doing these days?

[sikeston34m]

We finally got a break in the rain, and even though those nasty puddles are scattered around, I had to try this custom wind.

I have ran the factory 5 turn Delta wind on the 3530 in the E maxx before. It performs well. I ran it alot, so I'm really familiar with it's performance.

Today, I found out how the 3 turn Wye wind performs. It runs cooler than the Delta wind. I know the math says that the KV is supposed to be slightly lower, but top speed and acceleration are much better.

This motor makes MORE power! It also starts better.

I can easily take off in 1st gear OR 2nd gear. I can grab WOT from a standstill in 1st anytime and it responds perfectly.

When starting in 2nd gear, it still doesn't like the 1st or 2nd step in the throttle, but anything beyond that is just fine. I can grab WOT starting in 2nd gear! It blasts out of the hole with great control about 90% of the time. The other 10%, it kinda screams at me like Metalman described his was doing.

My conclusion is, several things add to the improved performance.

1. Lower internal winding resistence. Any wind irregardless of number of turns or termination will perform better, the lower the resistence is. I have a feeling this makes it draw more amps, but also produces more Watts of total power!

2. I believe the Wye wind is MUCH better for this type of application. It starts under a load better. I also believe it is more efficient, hence cooler running.

I did the test run on 15C 4000mah 4S configuration. I ran it hard and it lasted 25 minutes. This motor performs like the factory wind on 5S Lipo, but does it on 4S and starts better.

I will now proceed with the AXI 4130 rewind. I found a different brand 4130 6 turn Delta that's rated at 515kv. I'm thinking about 3 or 4 turn Wye termination should be just about right.

More on that as soon as my winding wire gets here. I believe the mail is pretty congested in some areas right now because of the holidays.

[johnrobholmes]

With mixed throttle you could have variable braking or throttle from front to rear.