Hmm, tough one...
This must be a x-ray generator based machine, at this consumption. One simple sollution would be 20X24V/100amps accumulators, coupled in series, which offers 480Vdc. Are you sure about the voltage? Isn't it 380vac/3phase? But that depends on your machine. Most of wall powered equipment requires AC power. However, some of them can be DC powered. For example, a power supply which have a 50Hz transformer as a primary energy transformer cannot be DC powered, but a SMPS power supply can, because at the input, after EMI filters, an AC to DC converter (bridge+condensator filter) always exists in SMPS. Check the schematic of your equipment, and if the power suppy (supplies, all of them) is SPMS, then you can put DC on it. Also, you will have to use a high power switching relay ( nominal current at specified power rate seem to be around 77 amps), so the relay must have switching capability of at least 100 amps. Also, between the relay and equipment you must insert a serious filter, to compensate the glitch inserted by the relay. It is a general idea, do consult other people and take care...your equipment seem to be expensive.