Hi Anthony,

Ok, so which machine are you playing with?

Have you got 380V 3 phase available or just 220V single phase.

Yes changing motors can be a real pig, unless you can get them with a matching shaft ( or larger and turn down to fit orig timing pulleys). The timing pulleys on many of these machines are american inch sized. Expensive, compared to metric. Changing the screw pulley to metric is possible, but a LOT of work.

Keeping the SEM motors is fine if they are good. ( we have spares) changing tacho ( resolver etc) for an encoder is not hard. Cheap from Aliexpress too.
If you have the same bosch driver boards as mine, it looks like they could be used.
Yes getting 180V DC ( I think) from a 220V AC supply will not be cheap, unless you are very lucky.

This is what put me off using them and going onto 220V AC servos instead.

Re Acorn, try contacting Chaz who posted above. He was using one on his.
He is pretty stretched time wise right now, but its worth a try.
He will no doubt also mention the cheap, offline ( non PC required) controllers that are starting to get popular now.

I went the CS Labs route myself.
Keeping vary speed and running inverter for head motor. Keeping the pneumatics too.( for now)

No where near finished on mine though. So I don't have much more to share.