Please see 1st picture on my website - Control box http://malamuterun.co.uk/cnc/homemade_cnc_mill.htm
There is two power sources.
1. Toroidal transformer with 25Abridge and capacitor at the top for PM752.
2. 25V power supply at the bottom for PCPPS-3 from zapp.
Two power suppliers share ground/negative.