TRIGGER FOR AN ELECTRIC SWITCHING APPARATUS AND ELECTRICAL SWITCHING APPARATUS COMPRISING SUCH A TRIGGER

摘要

A magnetothermic trip unit (6) comprising: a thermal trip unit, a magnetic trip unit, and first and second actuation levers (22); the thermal release comprising a bimetallic strip (30) adapted to deform to actuate the first actuating lever; the magnetic release comprises a movable armature (34), a fixed armature (32) and an electrical conductor (36); the movable armature being adapted to move to actuate the second actuating lever; the electrical conductor and the bimetal being electrically connected in series with each other between first and second connection terminals (10, 12) of the trigger assembly. The moving armature is connected to the first connection terminal, the fixed armature is connected to the second connection terminal, and the respective contact areas of the fixed armature and the movable armature are made of electrically conductive materials which have low weldability between them.