Re: Reversing Transformer connections
I agree with Jim. As a former applications engineer for a large electrical manufacturer that impart supported DTDTs we never advised a customer that it would violate a warranty if a 480-208y/120 transformer was applied as a step-up transformer and that its only to be applied for step down use. It was a matter of installing it correctly, that is unbonding the neutral(X0) from the enclosure which it is normally supplied with and feeding X1, X2, and X3 only, and feeding and addressing the 480v delta as to if it should be corner grounded or not. Since the taps are on the HV side, adjusting the taps is to though of in reverse which can be a real brain teaser.