Vacuum switch contact system with coaxial contacts - inhibits movement of contacts so they only close at null current point and when contact coating is solid

摘要

The contact system for a vacuum switch has coaxial contacts (4, 6) and at least one of the contacts (5) moves axially and has a current supply line (8). The current supply line (8) has an electromagnetic inhibitor (20). This inhibits movement of the contact (5) through mechanical friction force. Thus, the contacts (4, 5) are only reclosed around the time of the current null point and when at least part of the contact coating has solidified again after a short circuit to prevent the contacts fusing together. ADVANTAGE - A simple system to reliably prevent contacts from fusing together when they re-close after a dynamic opening upon a short circuit.