Is there a thermal breaker or other mechanism that protects the motor

[kahn]

This is my second e-bike. The first was a conversion with a front wheel motor. I was pedaling up a really long, steep hill and as I got near the top, the motor cut out completely. I did initially panic - had I killed the motor or system. I had done this hill a few times before but this time - STOP. It did restart a few minutes later. I presume there was some kind of protection that kicked in. I never definitely found out what happened other than it stopped and then restarted.

So my question is does anybody know if there some similar mechanism in my Specialized Creo? A breaker or some thermal sensor?

 

[jodi2]

Hub motors have their optimum RPM range. Depending on the type of ebike/motor speed limit somewhere between maybe 20 and 35 km/h. Uphill at very low speed/RPMs (let's say at 10-15km) they work unefficient and slowly overheat and the cooling wind is missing, so they overheat even more until power/current is reduced to protect them. If the overheating continues, they can switch off completely and to recover power you have to wait for the motor to cool down. Early hub motor versions many years ago did not reduce power or to late and were even damaged in that case.

A middle motor benefits from the gears like the rider. So it normally runs always in it's correct/best RPM range, so less tendency to work unefficent and to overheat. I'm not sure if or which middle motors drives have a thermal protection like this, maybe all. But it's usually not necessary/never activates and for the Creo I've never heard or encountered myself something like this. On the contrary, the Creo doesn't have peak power over the marked watts like many 250W standard drive do and can give more watt for a short but limited time. The Creo always gives max. 240W, and as I read somwehere (here?) if claimed also permanently until the battery is empty (maybe not in the Sahara at 50 degree celsius..).

Short answer: No. Or if so it doesn't really matter in real life...

 

[rich c]

Not technically perfect maybe, but I think most controllers are the weak point for heat buildup. They are tucked into places like battery boxes or inside the hub motors. Generic controllers are covered with aluminum heat sink style box. The motor always has something spinning in it. But I have seen motors where the varnish on the windings show signs of color change from the heat.

 

[jodi2]

The controllers inside hub motors were a big problem in early hub motors and died quiet often.
But I've never heard of burned controllers at middle motors. But on the other hand quite often mechanical problems in the mostly geared middle motors, while hub motors usually are mechanically a no brainer. If spoke/rim/wheel building are good...