There are basically two types of brushless servo, BLDC with hall style commutation and AC with sinusoidal commutation, in general the former are easier to mix and match drives to.
The BLDC usually have either true hall effect devices or equivalent tracks on the encoder.
AC sinusoidal come with a few variations, but are often fitted with a resolver, which makes it a great deal harder to match up.
In the past I have removed the proprietary encoders on Fanuc AC types and fitted them with a BLDC commutation encoder.
If they are BLDC motors, then A-M-C or Aerotech or Copley drives can be used, but analogue input. There are others if you want step/dir.
I have tried the CUI brushless types and could not get consistent performance of the standard optical type encoder.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.