... 2)No.3 with International Patent 3)Anti-theft,Anti-tamper transformer 4)lowest loss,small size 10-20KV S13-M ... Artiicial lamination, stacked, split iron yoke plug,5-6 working procedure decreasing compared with stacked core ... standard Q / CSG 11624-2008,5.7.ComparisonNote: S7, S11-M GB transformer No-load loss value ... than the S7, only 3 years and 5 months that recover the initial investment costs, ...