I have a vague recollection of once having seen warning information about plugging certain types of synchronous motors (like the one with my Scout) into AC regenerators. I don’t recall if it was in the Scout’s manual, or in the manual I had with my old PSA P500. At any rate, as a result I’ve always erred on the side of caution, and didn’t plug it into the P500 when I had it, and don’t plug it into my P3 now.
Edit: it was from the P500 manual, and it was only a warning not to use Multiwave: “Any turntable or equipment with AC synchronous motors, such as some cooling fans should not be used with MultiWave II. This equipment must be used with 60Hz SineWave mode.”