ELECTRICAL WEAR OF CONTACTS IN LOW-VOLTAGE, HIGH-CURRENT EQUIPMENT

摘要

High-current electrical equipment (rated current 50-150 kA) is used to shunt electrolyzers, in order to ensure uninterrupted operation of electrolysis shops in chemical and metallurgical enterprises. Such equipment must not only transmit a high load current for a long time, but also switch this current off when maintenance of the electrolyzer is required. Therefore, it is of great importance to increase the overall number of switching operations and correspondingly the electrical wear resistance. The operational reliability of high-current cutouts, their working life, and the switching wear resistance depend on the correct choice of contact system. We know that an arc discharge arises at breaking contacts if the current and voltage exceed certain critical values. For example, at copper contacts in a dc circuit, an arc may arise at currents above 0.5 A and at voltages no less than 15 V. At smaller voltages, opening of the contacts is associated with a spark discharge.