CONTACT TRANSITION IN METAL ARMATURES

Metal armature contacts often transition from a low voltage (less-than-or-equal-to-IV) to a high voltage (< 51 V) state. The high voltage state is characterized by arcing and considerable rail damage. It is desirable to delay or prevent the transition. Reliable prevention of transition has proven difficult because no validated physical model of the transition has been demonstrated. In this paper we show that armature contacts are adiabatic and that transition can be accurately predicted from basic physical principles.