I bought a couple of HXT 2730 motors a few months ago and they were 3000kv. My bad. They arrived and were useless. There is no prop that is small enough to work. I tried a 4x4 and it screams to no end with no useable thrust. Anything bigger will overload the motor or ESC.
I took one apart and took a look. These are wound with some very fine wire that is stranded larger wires.
Anyway, I unwound the motor and threw away the many feet of wire. I then ended up with a nice naked motor with 14 magnets and 12 teeth.
Perfect for DLRK (Distributed LRK) windings!
The LRK windings were designed by Lucas, Retzbach and Kühfuss.
I had some 0.4mm magnet wire around, so I started looking into how to wind these things. There is more to this than meets the eye!!
I found a thread over on RCgroups for winding just this motor. Ok. Perfect!
Here is the thread:
www.rcgroups.com/forums/showthread.php?t=736580I wound this motor according to that DLRK Wye winding and it actually works! It took about 30 minutes to wind and finish the motor. I was surprised at how quickly it goes.
I then mounted it vertically with my vise and stuck it on one of my scales that has the tare feature (where you can put weight on it and zero the scale).
Having no idea what the KV or power of this thing was, I started to just throw props on it with a 30 amp ESC and 3s batteries and measure the force on the scale.
Lots of props were tested...
The best was the GWS 8x4 prop with a prop saver, believe it or not! 22 ounces of thrust! There was actually more from bigger props, but the motor got HOT.
WOW!
Then I took my trusty ole original F-22 off the wall and clamped the nose in a vise. I placed that on the same scale and zeroed it all out.
Powered it up and it has almost the exact same thrust!! 0.5 ounce less. That was surprising. That is running an HXT 2730-1500kv motor.
Well, the DLRK winding is a lot quieter, even if it doesn't have any more top end power. It does not squeal at all like the HXT does. It has virtually zero magnetic 'cog' or like I call it 'compression' when you turn it manually. So the DLRK wind will spin freely in the air with zero throttle.
It is amazing how the motor build style affects it's attributes.
Well, I am happy that I was able to convert that high kv motor to something useable and I learned a lot in the process. Nothing that would let me know how a brushless motor winding applies to it's power and KV rating though. Nothing that says this number of wire windings at this or that direction will absolutely result in this power and that RPM KV. It's all black magic, I think.
I do have a new appreciation for these motor builders now!
Kent
