liveforphysics said:
It looks like a fine little motor for a light scooter or something.
You're a good man for taking it apart to measure it and show us the guts. Thank you.
Yes, thx Nieles. Not that it matters but the magnet count must be an even number.
Luke,
You look at it and only see a 10.5lb scooter hubbie, but I look at it and see a potential self ventilating RC killer in the 5-6lb range that is simple to implement. GM's motor test report shows it to have a Kv of 12.4 . The thing concerning me is the peak efficiency of 80% at 36V. The laminations look nice and thin, so unless there's an overall design flaw or they did something like use regular steel for the lams, the motor should be capable of much better. Maybe that just not a high enough voltage. My hubbies do upper 80's in efficiency, but that's at more than double the rpms of this one at no load 36V.
First I'd cut the wheel off and get it down to the raw motor, and see how it handles a 20s batt pack with a 20A limit on the controller as an easy to install mid drive. If it seems happy at that 1500W peak, then I'd go to town:
First a rewind to triple the Kv and greatly increase the current handling and operating rpm.
Turn the housing into a centrifugal blower expecting to see 2krpm+. Assuming the rewind left a nice pathway between the coils, Thud style, I'd set the blower up different than I've done other hubbie ventilation. On this one I would almost totally block flow through the stator spokes. Instead, I would take air in near the center on one side, with exit holes only in one cover on the other side, so the cooling flow would be forced through the windings. If that didn't flow enough air due to the small diameter, then I'd mod the intake side with a larger bearing and go active with 2 or 3 server blowers.
The end result is mid drive that would fit on the chain or seat stays of most bikes just by going to a 20" wheel, with a simple reduction to the wheel. Run it at 24s and 60-70A and you're in business with nice compact and lightweight power for the average Joe.