Alan B wrote:
Some fresh Cromotor data:
Cromotor 50mm wide stator 18x4 winds is 9.3kV and should be available by mid March. Just keep checking the 1st page of this thread [Greyborg USA Dealer thread] for updates.
We had seen the Kv before, but not the wind data, though I suspected it from writing inside the motor in photos. 18 strands, but only 4 turns!
I'm going off the writing too. Not a motor winder so someone would have to tell me how to count it exactly, but I can tell you that there is a bundle of what looks like 18 strands in parallel going to the teeth. It's a beefy SOB for sure. As for power. Mine took 10KW for 10 mins of playing around really hard racing cars in the video doing 55+ mph and was only warm. Wheel size makes a big difference on what you can get away with because I'm able to get my motor into the efficiency range really quick with my 21" diameter tire at 100% throttle. I'm looking at ebay right now for a 6ft long K-type thermocouple to install into the winds so I can monitor the motor temps while riding. I do know that after checking the motor at 5 mins and 10 mins after turning it off it was quite a bit warmer, about the max my wimpy super sensitive fingertips can handle (probably 55Cish).
If you plan to go nuts, ventilating the covers is always an option, but I wouldn't do that until after testing it thoroughly.
I'll probably spend some of my own money in a little while and take one of the motors, have it laced into a 26" wheel and test it out, but I can tell you that keeping a motor in a large diameter wheel under 100V is a good idea, just feed it amps and you'll get one heck of a grin. I have to keep my phase amps artificially low to keep the bike from looping at lower speeds. I'm going to see if my friend will mod a swing arm for me and make it 16" longer instead of my current 8" longer with a mount for a longer shock I have so I can really feed it some phase amps and get some motorcycle like acceleration. Only good for exhibition, but I have another identical frame and want to see what this thing can do.
I also can't wait to get my own Greyborg Frame and build it. My wallet can sure wait, but I need one for demo purposes and after riding a much earlier and less refined one I was quite impressed.
don't mean to spam the post, just trying to provide what info I can, hope you guys don't mind, if you do, just PM me and I'll edit.
Greyborg Hub Motor, Lyen 18FET, Customized full suspension kids MTB. Top Speed 61 MPH
9C 8x8, 24S2P LiPo, Lyen 12 FET, Diamondback Recoil Comp. Top Speed 42 MPH