One 25 KVA transformer is mounted to the utility pole which serves several homes and a small machine shop. The machine shop is looking into converting from single phase power to three phase power. The three phase choices from the power company are 120/240 Delta and 120/208 Wye. 75 KVA total three phase should be enough for the machine shop and allow some future expansion. Are either of these choices capable of using the current transformer and just adding only two more to make up the other two phases. The prefered way would be to choose either the Delta or the Wye so that the power company cannot utilize this existing transformer as one for the three phase bank. Meaning that the machine shop would not have to share the full capacity of the three phase transformer bank with any of the homes. The homes would only share the current single phase transformer. The end result (if possible) would be a utility pole with either four single phase transformers on it or one single phase transformer and one three phase transformer.
