For example: Agilent E4440A or Anritsu 68369
DC Power Supplies
Power 10 P63C-12.5265
12.5V, 265A, 50MV, 3.3 kW to 10 kW, 3 Phase Power Supply
Manufacturer: Power 10
Power 10 P66A-12.51060
DC Power Supply, 12.5 V, 1060 A, 13250 W, Programmable
Manufacturer: Power 10
Power 10 P66A-12.51325
DC Power Supply, 12.5 V, 1325 A, 16560 W, Programmable
Manufacturer: Power 10