It sounds to me that ScottyUK's suggestion will get the job done. Since you are cascading the UPS's, you will need a utility source incase the backup UPS requires service. A panel with two breakers and a mechanical interlock will suffice, since a break in power would be allowed on the backup...
http://www.ch.cutler-hammer.com/NASApp/cs/ContentServer?pagename=C-H/Common/AssetTemplateLink&c=Apubarticles&cid=984847516544&Sec=learning&uid=Variables.uid provides an online course on all facets of electrical power engineering.
I have an old Westinghouse pamphlet that describes in detail the calculations and the connections. I also found a diagram in the Square D technical Library (www.squared.com) under Transformers (Dry Type Transformer Application Guide). Both of the sources indicate that you can expect to get 433...
jwerthman is correct. If the motor is a special motor, or a part of a piece of equipment, you may want to utilize a three phase boost circuit to provide a volts/hertz ratio that is comparable to the v/hz ratio of the rated motor. If not, then a motor of the proper rating is in order...
While some of the tests you have outlined may be "type" tests, you have specified that the tests be run as part of the factory testing. We typically ask for all the tests you have indicated and ask for measurements of fuel consumption, vibration analysis, coolant temperature and...
From the basic three phase power calculation, KVA = VOLTS X AMPERES X SQRT(3)/2. Your 800 ampere, 208 volt additional load is 288 KVA. The input and output voltages are to be found on the nameplate of the existing transformer. I suggest that you engage a profewssional engineer to assist you...
