I could send you a photocopy of the manual for the Kity 522 spindle moulder if that would help. Seems to cover most of the basics though Kity were never that good on manuals. It’s multilingual.
Not sure how to send stuff by post though. Can’t do a file, it wouldn’t be readable.
Oh, in that case it really is winding breakdown. It superficially looks ok until you get to the middle of the windings but then they are blackened etc. It will run fine until you put a load on, then ……..
I speak from experience, the motor on my Inca- Startrite was just like that until rewound...
AC motors have a lifetime. Yours is apparently 8 yrs old. Past overheating and even long normal use can cause breakdown of the insulation in the windings. You can’t see it but it sounds as if you are experiencing the results. Maybe taking it to a rewind specialist for a check could dave you a...