I have often wondered how long a non VFD rated motor will last when used with a VFD In a hobby like environment?
I'm running a test, sample size one with my drill press, and an eBay "special" used motor that was used in a commercial dryer for who knows how long?
It's been about two years and so far it's working fine, who knows maybe it will blow up tomorrow?
I wonder that too. On a mill or a drill press in a hobby environment, I can't imagine a big concern. Loads are low cuz it isn't being pushed, duty cycle is low cuz we are not experienced enough to be rammy, cuts are shallow cuz we are scared of breaking a tool, and we have all day to make a $20 part.
That's prolly why we don't have $50,000 machines too.