CIRCUIT BREAKER MAGNETIC TRIP DEVICE

摘要

C-1749(SWGR/CBO) CIRCUIT BREAKER MAGNETIC TRIP DEVICE A magnetic trip unit for a circuit breaker having an armature and a plunger; the armature completes a magnetic path through the poles of a permanent magnet; the armature and plunger are biased toward trip position but are held by the permanent magnet and may be restored to the position where the armature completes the path through the poles of the permanent magnet. A trip coil is provided surrounding the permanent magnet and armature. A casing of magnetic material surrounds the trip coil and extends below the armature; this casing also has top and bottom walls of magnetic material and an inner cup shaped sleeve bearing against the bottom wall and against one pole of the permanent magnet. Energization of the trip coil establishes an additional magnetic path through the armature and the said one pole of the permanent magnet which opposes the magnetic force of the first mentioned magnetic path and permits the bias on the armature and plunger to move them to trip position.