Hi Nicholas,

These machines where never built to go fast and it's the voltage that is limiting the speeds your getting.
About 18mths ago I converted it's bigger brother Hsr1000 for someone and re-used the old motors without any trouble so won't need to replace them. However I did Fit Fans because running higher voltage increases heat and being inside the cabinet didn't help. So fans will be needed to blow air onto steppers and pull air out of the cabinet. This is good idea anyway and IMO something the original should have had fitted, esp in the electrical cabinet.

The convesion I did replaced everything but the spindle Speed controller. It consisted of Leadshine DM542 Digital drives running 44Vdc using toroidal PSU and Cslabs IP-M Ethernet motion controller using Mach3.
This does mean the control panel on the front cannot be used like before as it's bespoke to the original controller but with some hacking you can re-use the tactile buttons. Then you can connect these to the IP-M inputs to allow jogging or turn on/off spindle etc.

This combination instantly doubled the machines usable speed with little spare if required. I seem to remember it left me tuned at something like 7000mm/min but would reach 10,000mm/min. The guy who own's it soley cuts 3D work and each job runs for 6-8 hours at time.

Hope this helps.