Transformer; Isolation; Pri/Sec:115VAC; 50/60Hz; 15VA; 1500Vrms; 3-5/16In.W; 1-15/16In. This prevents electrical connection, under normal or overload conditions, between the primary and secondary windings Triad isolation transformers from Triad Magnetics are power transformers for isolating equipment from direct connection to the power line. They are offered in a variety of voltages and case types. The transformers are constructed with nonconcentrically wound coils. The primary and secondary are wound on separate arbors, then assembled on a laminate core side-by-side separated by insulation.