they are A06B-0521-B042 3ph 8 pole, 2000rpm, 1Nm stall torque, 3 amp stall torque, 47v. 2500 pulse incremental encoder.

As you say can't imagine any different to any other servo, but I can't find a datasheet giving details like inertia and how much power is generated when braking

Having looked at the offering on various trade sites such as alibaba they have new 200v ac servos and drives for not a lot of money direct from china, which do not need a separate power supply, and should I wish to upgrade in the future they accept a 10v supply rather than step/direction. Buying one of these should be a plug and play setup, whereas trying to get the Fanuc servos up and running without the relevant info could be a lot of hassle.

Alternatively I could get some AC servos and drives from CNCdrive for not a lot of money, which are also 48V.

I have tried contacting CNCdrive twice about their servos and drives, as to if they offer a 2500 line encoder instead of 1000 line, and if their drive will support this, or if they know if it will run a fanuc servo but have had no response. Doing the calcs though with a 1000line encoder which is their standard fitment it still gives me a resolution of 0.0025 which is more than enough.

Is there any advantage going to a 200v servo over 48v, apart from not needing a separate power supply? The 10v input is not important at the moment, as I have another machine that I could fit the step/dir input drivers too, and upgrade this machine at some point in the future