... .63~10MVA 3.S9~S13 transformer Ring Transformer, Power Supply, Electrical EquipmentStandardsGB1094.1~2-1996GB1094.3,.5-2003GB/ ... free copper3.Multilayered cylindric structure for high-voltage winding, toroidal structure for low-voltage winding, fine performance4.New insulation ... resisting treatment, maintenance freeS9-M-630~10000/10 Ring TransformerPrimary voltage: 6, 6.3, 10, 10.5, 11kVTapping ...