Testing appts. for HV metal cased switches - uses high case voltage with several contact pairs per pole

摘要

A testing device is for metal-encapsulated high voltage switches (4) with at least two contact pairs per pole. It uses a voltage applied to the case (4a) which is insulated from earth, of opposite polarity to the test voltage. This method allows for voltage effects between the test voltage carrying part and the case in the event of supply voltage failure. At least one interrupter pair (4') is supplied with current and voltage while the remaining breakers (4", 4"') are shorted out to the node of the loaded breaker (4') approximately one millisecond before breakdown using an auxiliary switch (14).