I have a Sieg X3 that I am converting to CNC, I have built the Embedded Electronics MicrostepPLD boards and all seems to work very well bench testing on a small power supply. I need to build a full size power supply and am having trouble spec'ing the Capacitor for the unit, I haven't bought any components yet but here are my thoughts:

36v 20 toroidal transformer set up with a full wave bridge rectifier. My question is how do I determine the size of the Capacitor for the unit?

Thanks

Randy