Patent ID: 7400482

Claim:
A circuit breaker comprising: a housing; separable contacts; a bimetal electrically connected in series with said separable contacts, said bimetal including a temperature dependent resistance and an output having a voltage representative of current flowing through said separable contacts; an operating mechanism structured to open and close said separable contacts; a temperature sensor distal from said bimetal, said temperature sensor including an output having a signal representative of ambient temperature; and a trip circuit cooperating with said operating mechanism to trip open said separable contacts, said trip circuit comprising: a first circuit including a first input electrically interconnected with the output of said bimetal to input said voltage representative of current flowing through said separable contacts, a second input electrically interconnected with the output of said temperature sensor to input said signal representative of ambient temperature, a real-time thermal model structured to provide a corrected temperature dependent resistance of said bimetal as a function of said voltage representative of current flowing through said separable contacts and said signal representative of ambient temperature, and an output including a current value which is a function of said voltage representative of current flowing through said separable contacts, and said corrected temperature dependent resistance, and a second circuit including an input having said current value and an output structured to actuate said operating mechanism in response to predetermined current conditions.