Brushless servo amplifier

I have recently acquired five brushless servo amps (eBay), units are manufactured by Aerotech,Inc. I'll be using these for upgrading my CNC-mill from open loop (stepper) system to a closed loop one.

 Model number is BA20-160, it means peak output current rating of 20 amps and output voltage in the range: 80-160V. With some modifications to the power supply of the amp the output voltage can be anything between 0V to 320V. I have already tested one amp with a 40VDC servo motor. These units can be configured to drive brush or brushless servo motors.

 One amp will be used for driving spindle motor (DC) and four amps will be used for driving AC servo motors (X Y Z A).