Means for arc suppression in relay contacts

摘要

In a circuit having a electro-mechanical relay the contacts of which are subject to arcing, a shunt across the electro-mechanical relay configured to begin conducting electrical current across the electro-mechanical relay prior to closing the electro-mechanical relay contacts and to continue conducting electrical power across the electro-mechanical relay for a predetermined time after the onset of separation of electro-mechanical relay contacts pursuant to discontinuance of current flow through the elecro-mechanical relay. An optical coupler is employed to detect the current flow through the relay coil and activate a shunt device to initiate current flow around the electro-mechanical relay. The shunt device is configured to be substantially non-current load carrying while the electro-mechanical relay is closed. Utility is found in protecting relay contacts against damage due to arcing.