Protective disconnector with bimetal switch shunting release coil - opens switch when overload occurs and thereby triggers release

摘要

The disconnector, with electromagnetic release, is triggered by short circuits and overloads. A bimetal element is connected in parallel with the release's coil and is held rigidly at one end and free to move at the other the free end carrying a contact. When an overload occurs the bimetal element snaps open rapidly thereby increasing the current through the release's coil and causing the disconnector to open. (The coil's resistance is high). A PTC or NTC resistor may be connected in series with the bimetal element.