dogman dan wrote: ↑
Sep 26, 2018 8:02 am
When you run hard, then suddenly stop, the motor loses all wind cooling, and the inside temp will spike more than you might think possible. When I fried halls in smaller motors pretty regular, they typically died while the motor was stopped, despite my attempt to run a bit of cool down time at low speed and power. Basically, once outside temps got to about 40c, the motor would not cool enough, and I'd fry the halls in a motor. Why would cooking off your halls not cook off all three? Assuming they did cook off.
Even very small, like 3 mm holes in the hub cover can help a lot with quicker cooling of the motor when you stop, even if pretty much totally ineffective while the motor runs. It also lets you smell it when you stop, when you are cooking off the windings. poor mans temp monitoring, stop when you smell fairly toasty windings, before you smell burnt.
My hall sensors actually died in the middle of a ride; I had throttle and power then all of a sudden I had nothing...
I replaced all 3 sensors with new, higher quality sensors by Allegro Microsystems even though I verified that only 1 sensor was broken. I believe the broken one was making intermittent contact which was allowing the controller to pick up its readout for a few seconds, then lose it. I did not pot the sensors but I am now worried that they will break again in another month or two. If I get stranded 20 miles away from home, I will seriously re-consider ever using a sensored controller again.
Thanks for everybody's help and input.