My motor did BURN
eyebyesickle said:
casainho said:
For the guys that got theirs motors to much hot up to the point that the motor stops for some minutes, did you found after that your motor did loose for ever torque??
No, in my experience if the motor cuts off due to high temps it comes back fine...
So, yesterday I got for the first time the high temperature cut-off of the motor while I was trying to discharge fully my battery and fast so the motor current was almost always over 15 amps.
Today I went to do another battery pack fully discharged and I noted that my motor was asking the same power as 900 watts but it was lacking some force/torque!! After some comparison with other ebike running with same TSDZ2, I found that my motor wasn't working properly and so I decided to open it:
So as we can see, some of the motor phase wires insulation seems that got very hot as also the motor metal parts are clear with a more dark/brown color. I would say the temperature was at least 100 degrees. And
I think the magnets inside that motor did suffer some expressive demagnetization and so the loss of the motor torque forever. Here what I found only about this subject:
The Curie temperature of high-grade Neodymium (with added terbium and dysprosium) is 320C / 600F. However, common neo magnets are made from the cheapest grade, and can start to lose some of their magnetism at around 80C (170F).
E-bike motor magnets are a grade that is slightly higher than the cheapest variety, because they are often subjected to higher temps than they should be by unsuspecting customers. Years of posted experiments by real E-bikers on endless-sphere have produced a commonly held rule-of-thumb to avoid heating your E-bike motor to above 95C (200F).
https://www.electricbike.com/motor-tech-learn-the-terms-part-1/
Next I went and exchanged the motor for a new one I had in stock and I got back the full torque of TSDZ2!!!!
So, my question is: how can we avoid motor heating TSDZ2 motor over like 80C to avoid losing forever motor torque/demagnetize the motor magnets??