Electrical trip switch mechanism comprises permanent magnets set into a coil former that respond to overload or short circuit current

摘要

The switching device has a release mechanism (10) that has a pair of permanent magnets (16,17) separated by a core (18) and a gap having a non magnetic material such as aluminium (30). The magnets are set into a former (19) supporting a coil. The magnet axial movement is limited by a projection (35) and the trigger level is dependent on the non magnetic material.