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→6.1.2 High Electrical Loads
At high electric loads that usually occur in power engineering devices the switching phenomena are mostly related to arc formation. For most applications the management of the switching arc is the key problem. Depending on the device type different require-ments are dominant which influence the selection of the contact material. Similar to those in communications engineering, issues related to the switching characteristics and current path have to be considered.
*Make operation<br/>Make erosion caused by pre-close and bounce arcs<br />Welding mainly during bounce arc<br />Mechanical wear mainly through bounce and relative motion<br/>
*Current carrying through closed contacts<br />Increased contact resistance and temperature rise <br />duringnominal load<br />Welding through high contact resistance during overload andshort circuit load<br />Welding during dynamic separation of the contacts with arcing
*Break operation<br />Arc erosion during opening<br />Arc movement<br />Arc extinguishing<br />Mechanical wear
switching current and
numbers of operation
==References==
[[Application Tables and Guidance Data for the Use of Electrical Contacts#References|References]]