While I take everything from mac with a heaping of salt
, I don't discount that he has a valuable perspective. It may be one which appears to be skewed by experience, but since I have experience only with a high spec world and he's been dealing with the full gambit, I wouldn't discount it at all.
Do I think he's rude and fails to actually back up his claims with anything beyond hand waiving? Sure. That doesn't mean he hasn't seen what he's seen. I encounter other engineers (myself being an ME/EE mostly from Automotive startups and servo motors) all the time who have tremendously valuable experience and totally wrong interpretations about root cause. Correlation and causality are not at all the same, but it's so easy to conflate. I've spent almost half of my career hunting down causality rather than correlation and dang is it a tough thing to do.
So just to summarize, don't necessarily take everything from mac as gospel, but don't dare discount the experience. Whether or not he's attributing causality correctly or not, I have yet to form an opinion in any particular case. I do believe he's not lying about correlation.
That means: Underrated drives fail when paired with higher motor ratings is likely true. The WHY is not yet determined imho. I
believe it's due to drive design shortcuts in low quality drives and/or user error (VERY LIKELY AT LEAST SOME USER ERROR ALWAYS). I don't know what the cause is. I have in my mind and have posted my suspicions, but each drive failure case would be it's own investigation.