openinverter forum

Ive had a broken spider gear sitting on my desk at work and noticed something. All the teeth had hairline cracks. It would seem that once they reached an adequate depth, the powdered metal structure decided to quit.

Interesting! So the teeth are softer and more ductile, the inside stuff is more brittle. Fun. (or maybe it's the other way around, I am no metallurgist).
Could that theoretically be an early warning sign for anyone who is driving their motor as hard as you are?

jon volk wrote: ↑Wed Feb 03, 2021 4:55 pm Ive had a broken spider gear sitting on my desk at work and noticed something. All the teeth had hairline cracks. It would seem that once they reached an adequate depth, the powdered metal structure decided to quit.
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What it looks like you are describing bus classic metal fatigue, where micro cracks form due to manufacture imperfections and geometric features, that when cycled slowly open up the crack to failure. The characteristics are defined by an an curve which is logarithmic, as you are operating your motor at quite high power levels, a small increase in load massively decreases the life. (You might be able to tell this was my job till the aerospace went boom and have had 2 such failures on my road (cycle) bike due to atigue).

Based on what can be seen though (particularly if you follow the sandy Monroe videos), Tesla seems to be very good at feeding design changes back into production, so you new unit will likely have design changes or improved manufacturing processes added to remedy it.

Some reading if you get bored
https://gearsolutions.com/features/esti ... igue-life/