I have a situation where I need to power a intermittent single phase large load with a three phase transformer so I will not be using one leg. Its short term hook up for two to three years at best so I do not want to buy a transformer ($$$$$) when I have a 3 phase dry transformer collecting dust of sufficent size. I have not come up on this type of config before so I have my conserns. Such as
*Would it be kosher to wire and tap only two of the three coils?
*if not, what issues would I have if I were to wire the high side 3 phase and only use two legs where the amperage in theory be upto 100 amps, 90 more realistically and only intermittenly?
Basically it is a open delta where Phases A & B are connected in opposing series and Phase C is connected in aiding series to the combined A & B. The output "L1"is connected to the free end of A, the "neutral" is the connection between B & C, and "L2" is the free end of C. The connection between A & B is not used.
This limits the unit's maximum power to 2/3 of full rating but is does load the 3 phase input equally.
That is what I'm planning to do. By maxing two of three legs while having nothing on the third leg, I dont know such an unbalance would cause any issues for the transformer and or the circuits or not. That would be a rather expensive smoke test if overlooked something