... /3phase, 2. bar form tap changer for tansformer use 3. electrical equipment 1.This kind of switch applies to the single ... -phase,three-phase,combination oil-immersed transformer of electrical power .2.The frequency of 50HZ,60HZ,rated voltage of ... ,rated current of 30A~250A;the voltage-regulating places are:central part,neutral point,can be directly fixed on the box ...