My mention of a “labyrinth seal” comes from the description of a Mafell FM 1000 WS which I purchased:
It was something of an indulgence (and also an investment, it was pricey, plus I had to get a transformer — the only reason I could justify it was that I do so many test cuts for tech support some days it felt as if I was spending more time wrenching than the machine was cutting), and I’m still working out dust collection, and it doesn’t seem to be available from the U.S. reseller anymore, but you can read the description of a similar unit at:
(but if you bought one, you’d be on your own for making a mount and working up dust collection)
No idea on the specifics of our VFD/spindle (I don’t have one, having committed to the Mafell before it became available) — check w/ the folks in Sales who should be able to provide any details we can share which aren’t on our shop page.