Dc resistancetest around group is an indispensable test project of transformer after the submission of pick up overhaul and change of subpick up switch. In general using traditional methods (bridge method and pressure drop method) measurement transformer winding group and dc resistance of large power inductance equipment is a time-consuming and time-consuming work. In order to change this situation shorten measurement time and reduce work burden of test personnel our company developed Dc resistance rapid test instrument (hereinafter referred to as direct resistance instrument). It adopts new power supply technology featuring stable performance rapid measurement small size easy to use high measurement precision and good data repeatability. Measurement transformer is around the group and large power inductor dc resistance ideal equipment