The influence of the contact materials arc-conditioning method on electric strength of vacuum interrupters stored in nonvoltage state

摘要

The electric strength between open contacts of a vacuum interrupter must fulfil the requirements of adequate IEC standards. For a long vacuum gap (10-14 mm) there is a strong relation between breakdown voltage U/sub b/ and charge Q/sub max/ as well as microdischarge onset voltage U/sub MD/. These chosen parameters can be treated as very good criteria of electric strength of a vacuum gap. In this paper the authors compared the electric strength degradation of chambers prepared with various arc conditioning processes. The test objects were commercially made medium voltage (12 and 24 kV) extinguishing chambers of a vacuum interrupter with CuCr sintered contacts.