THERMOMAGNETIC CONTACTOR Russian patent published in 1998 - IPC

FIELD: electrical engineering; thermomagnetic contactors enabling heating temperature control and power circuit disconnection in case of overheating. SUBSTANCE: contactor has heat-resistant insulating base 1 accommodating thin contact plates 3 and disconnecting leaf springs 4, both rigidly fixed in position symmetrically relative to center; loose switching ends of contact plates 3 carry cermet contact members 5. Rigidly fixed below contact members 5 on contact plates 3 by means of fastenings is magnetic system arranged as follows: one contact plate 3 carries magnetic core 7 made of thermomagnetic alloy (for example, grade 10SCh1, 20SCh, 80SCh, etc., with Curie point Q_c= +110...+120^°C)) and other plate, high- strength permanent magnet 8 made of retentive material (such as alnico or magnico, etc., with Curie point Q_c= +870...+900^°C)); small air gap is provided between them in ON-position. When magnetic system is heated to 110-120 C and higher temperatures, magnetic core loses its magnetic properties and contact plates 3 open contact members 5 under the action of disconnecting leaf springs 4 and form separation δ. As soon as temperature decreases to normal value (lower than 110-120 C), magnetic core 7 acquires its magnetic properties again and is attracted to high-strength permanent magnet 8 of magnetic system; in the action, contact members 5 close and are reliably held in ON-position. EFFECT: improved economic efficiency. 4 dwg