Three-phase UPS transformaer using stand-by inverter of a single phase

A new three-phase UPS transformer for an uninterruptible power supply (UPS) is described. Its configuration is a magnetic integration of a three-phase ferroresonant transformer and a single- to three-phase converter. The three-phase commercial source takes over a load on normal condition. The three-phase output is supplied from the single-phase input port with a stand-by inverter in a failure of a commercial source. The structure and the control means become considerably simple in the new method.