Electromagnetic excess current cut-out - has nonmagnetic case containing movable magnet and section of damping oil

摘要

The excess current safety cut-out has an attracting iron piece attached to the housing at one end. An excitation coil is wound on the case. A yoke is mounted on the case, with an iron armature hinged on it. The latter responds when the excitation current in the coil exceeds a specified level, and is attracted to the attracting iron piece to break the circuit. Iron armature (4) has a projection (12) which forms a magnetic path parallel to the path through the yoke (3). This arrangement gives a large mechanical moment for a given current value.