CM R1R2R3 ABCN XYZN BB 1BB 2 BB 3 VARI ABLE INPU T LTST ABILI ZED OUTP UT L.T. AVR XYZN ABCN SD 1SD 2 SD 3 BB 1BB 2 BB 3 R1R2R3 HTVA RIAB LEIN PUT LTST ABILI ZED OUTP UT CM TRANSFORMER WITH BUILT-IN AVR