It applies the high quality epoxy resin vacuum impregnation, solidification through high temperature. The product has the features of energy-saving, good inductive line performance, accurancey resistance value, uniform distribution of coil temperature rise, high dynamic thermal stability, anti-short circuit, strong overload ability, good insulation intensity, good uniform distribution of eletromagnetic field, low loss, low temperature rise, long service life, maintenance-free, low noise, flame-retardant, pollution-free, small size, light weight, and easy to installtion and use and son on. Current-limiting reactors are ususally used in the distribution line. The branches derives from the same Bus are usually series with current-limiting reactors to limit the short circuit of the feeder line and maintain Bus voltage. On its surface do the resistance coating: to spray with the RTV of high insulation resistance and hydrophobic, make the surface of the reactor has good insulation performance and thus has good effect to limit the tree-technology discharge of the reactors products' surface. And thus ensure the reactors to run safely in the outdoors.