Patent ID: 7397339

Claim:
In an ambient compensated circuit breaker having an opening and closing mechanism for moving a movable electrical contact into and out of electrical engagement with a stationary electrical contact including a trip latch and a catch surface engageable with the trip latch for maintaining the opening and closing mechanism in the engaged contacts position during normal operation, an ambient thermostat metal compensation member coupled to the catch surface, a current carrying thermostat metal trip arm which bends upon being heated, the bending movement transferred to the ambient thermostat metal compensation member, the ambient thermostat metal compensation member bending in the same direction as the trip arm upon changes in ambient temperature to maintain a generally constant relative position of the trip latch and catch surface in response to such ambient temperature changes, motion from the trip arm upon selected overload current transferred to the catch surface through the ambient thermostat metal compensation member thereby separating the catch surface from the trip latch allowing the opening and closing mechanism to move the movable contact out of engagement with the stationary contact, the ambient thermostat compensation member having a selected thickness and length, movement of the ambient thermostat metal compensation being subject to the following formula: B (thermostat metal movement)=0.53 F (Δ T ) L 2 /t where F is flexivity (10 −7 /degree Fahrenheit), L is length (inches), T is temperature (degrees Fahrenheit) and t is thickness (inches), the method comprising the steps of changing the level of thermal compensation of the ambient temperature thermostat metal compensation member by choosing a single selected thickness and actual length for a series of different thermal compensation levels and changing the effective length of the ambient temperature thermostat metal compensation member by form in ribs into a selected size in the ambient temperature compensation member wherein the greater the size of the ribs, the less the movement.