I have a Generac 480/277 35kva back up generator. We are changing the in coming service from 480/277v 3 phase to 208/120 3 phase. Can the windings on the Generac be change for this new service ? Or do we have to purchase a set down transformer and place it just past the transfer switch on the out going feed when the generator is running. Also will the transfer switch still work whether incoming voltage is 480 or 208. If not what would we need to do? Any help would much be appreciated.

Thanks
Mike