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(11) | EP 0 232 172 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Switching arrangement with thermal and magnetic functions |
(57) A switch combining magnetic control and thermal control. A movable contact is urged
by a magnet into contact with a fixed contact. A bimetallic strip is capable of urging
the movable contact out of contact with the fixed contact upon exposure to a thermal
overload. For a switch responsive to both burglary and fire detection, a permanent
magnet urges the movable and fixed contact into a normally closed position. When the
magnet's influence is no longer felt, such as when a burglary occurs, the movable
and fixed contacts will separate. A bimetallic strip, when sensing a thermal overload,
will also move the movable contact out of contact with the fixed contact even in the
absence of a burglary. The switch responsive to both magnetic and thermal energy is
also used to protect a relay controlled circuit from thermal overload. |