Patent ID: 7030769
Filing Date: 2006-04-18
Classification: H01H

Abstract:
1. A circuit breaker for providing protection in an electric power distribution system, the circuit breaker comprising: separable contacts; an operating mechanism opening the separable contacts when actuated; a trip unit comprising a thermal/magnetic trip device producing a thermal trip by actuating the operating mechanism in response to persistent overload conditions and producing a magnetic trip by actuating the operating mechanism in response to overcurrent conditions; and a monitor providing a thermal trip indication when the separable contacts are opened by the thermal trip and providing a magnetic trip indication when the separable contacts are opened by the magnetic trip, wherein said trip unit produces said thermal trip and said magnetic trip independent of said monitor, wherein the thermal/magnetic trip device comprises a bimetal heated by current passing through the separable contacts and the monitor comprises a trip sensor sensing opening of the separable contacts, a temperature sensor sensing temperature of the bimetal, a processor generating a thermal trip signal in response to a sensed temperature above a selected value when the separable contacts open, and output means generating the thermal trip indication in response to the thermal trip signal.