The Delta/Star (Wye) Distribution Transformer, Model 8899, is a three-phase transformer that allows the mains voltage of an ac power network (i.e., the local ac power network voltage) to be adjusted, as well as the conversion of an ac power network from a delta configuration (three lines and a ground) to a star (wye) configuration (three lines, a neutral, and a ground). The star (wye) configuration is necessary for some exercises. Many mains voltage values are available. The Delta/Star (Wye) Distribution Transformer, Model 8899, operates at a nominal power of 5.4 kVA.