Direct Drive to Diff E Revo Build

[sikeston34m]

It's a 4130 AXI Stator. I wound it to a 4 turn Wye using 6 strands of 22 awg. It is tight too.

That's the crimp/solder termination that I talked about earlier. It works good.

[sikeston34m]

I got the custom wound motor installed. Even though it's dark outside, I had to go try it. MUCH Better!

Much better low speed driveability. Cogging is almost non-existent. I can make it cog by grabbing WOT from a stand still, But even then alot of the time it will blast off with the front end in the air. It will do 4 wheel burnouts on the concrete drive.

Torque is MUCH better. Top Speed seems a little lower on 4S than the 4120 660kv. I'm thinking this will be a GREAT 6S setup. I ran it for about 10 minutes and the motor was cool to the touch. It's 37 degrees outside, but I don't think temps are going to be a problem. I also put thermal heat sink compound between the motor and the mount.

Now that I have cogging under control, I'll start bumping up the voltage until I get the speed I'm looking for.

@Johnrob - Is there any way to estimate the KV rating of an AXI 4130 4 turn wye wind? 6 strands of 22awg?

[lincpimp]

Good to hear that this custom wind works better. The kv must be lower, if the spped is slower, maybe 280kv? That would be a wild guess!

[sikeston34m]

Originally Posted by lincpimp

Good to hear that this custom wind works better. The kv must be lower, if the spped is slower, maybe 280kv? That would be a wild guess!

No, it's alot higher than that. The factory wound 20 turn Delta was 305kv and that was using a really small ga. wire. The AXI 4130/16 Delta is 385kv.

Check this out:
http://www.rchotdeals.com/Products/r...or/A41308.html

It's a 4130 6 turn Delta rated at 510kv, but it doesn't show the Resistence values of the wind. Resistence means alot. Even if you have two motors with the same amount of turns, the one with the least resistence will make more power and more kv.

The Wye wind has 1.73 times the torque of a Delta but 1.73 times less kv for the same wind. That's why I dropped a few turns to make up for that.

I'm sure it's over 400kv, but I wonder if there's a way to figure this accurately.

[lincpimp]

Well you could radar both on the same number of cells and then fiqure it out backwards. I am sure that there is some mathmatical way of figuring it out. I see that my guess was a bit wild! I just thought you said it was slower on the same number of cells as the other motor.

[sikeston34m]

The other motor I was referring to was the 4120/14. It's a 660kv motor.

I didn't really get a chance to top it out good even on 4S. It's pretty dark out there and they just graded the gravel road in front of my house. It doesn't take much to slip and slip on that stuff.

[lincpimp]

hats cool, thought that you were talking about the 4130 motor you had in there before, I need to re-read the thread, my memory sucks! How is the new emaxx coming along? Are you going to do a custom wind, or the motor we were discussing? I have to finish my other rc projects before I start on the new emaxx!

[GriffinRU]

Originally Posted by sikeston34m

@Johnrob - Is there any way to estimate the KV rating of an AXI 4130 4 turn wye wind? 6 strands of 22awg?

Estimate - Hard
Measure - Simple

Apply fixed (measure) voltage - measure RPM
Spin with fixed (measure) RPM - measure voltage

[johnrobholmes]

Originally Posted by GriffinRU

Estimate - Hard
Measure - Simple

Apply fixed (measure) voltage - measure RPM
Spin with fixed (measure) RPM - measure voltage

Won't he need to use an AC voltmeter setting, and won't it give an RMS voltage out instead of the required DC input for the given speed? I can't find any info on how a 3 phase would be tested for kv.

[GriffinRU]

Originally Posted by johnrobholmes

Won't he need to use an AC voltmeter setting, and won't it give an RMS voltage out instead of the required DC input for the given speed? I can't find any info on how a 3 phase would be tested for kv.

H-Bridge is built-in into FET's

[johnrobholmes]

Originally Posted by GriffinRU

H-Bridge is built-in into FET's

You are talking of the ESC right? I'm confused now

[its me]

Hey sikes sorry if you answered this but what was the final out come of your motor selection (I get dumb founded by the tech talk LOl)? I would like to attempt (direct to diffs) this with the maxx im building.

[GriffinRU]

Originally Posted by johnrobholmes

You are talking of the ESC right? I'm confused now

Have your test motor attached to ESC and Voltmeter to battery connector, leave battery unplugged. Spin motor shaft and record peak voltmeter readings.
Do not forget about RPM, you need to know motor speed to calculate Kv value.