I'm retrofitting a DM4400(build log comming soon), and i'm replacing the stepper motors with these DC servo motors
What driver would you suggest? The G320X is only rated for 80VDC but the motors are 90VDC
I'm also looking for something to replace the spindle drive,
The gecko320x servo driver will work. The power supply voltage will set the maximum rpm the servo will spin at. The motor is rated at 6000rpm with 90volts. If you only need 3000rpm, you will need approximately 45volts power supply voltage.
You are also limited to 20amps current so the peak torque will be less than the max rated. You will need to calculate to see if that is enough for your application.