Electromechanical switching unit with non contact status sensing

摘要

The electromechanical switching device includes a number of non contact sensors to identify a range of fault conditions. Position sensors in the form of differential Hall effect devices (1,3,4) are used to monitor the switching operation, a short circuit condition and a contact welding condition. A current overload condition is indicated by a B field and for this a reed relay device is used (2). The short circuit and overload sensor outputs are coupled to electronic memory devices for resetting.