Patent ID: 7821376

Claim:
A method for adjusting a trip sensitivity of a thermal overload protection apparatus, the thermal overload protection apparatus comprising bimetals for providing a driving force for trip operation by being bent when an overcurrent is conducted in a circuit, a shifter mechanism for transferring the driving force from the bimetals by contacting the bimetals, a trip mechanism rotatable to a trip position at which the circuit is broken at a time of release, a trip latch mechanism movable to a position for releasing the trip mechanism from a position for restricting the trip mechanism by the driving force from the shifter mechanism, and an adjusting knob for adjusting a gap between the shifter mechanism and the trip latch mechanism, the method comprising: measuring a position of the bimetals and a moving distance at the time of trip operation of the trip latch mechanism so as to determine a gap between the shifter mechanism and the trip latch mechanism; determining an installing position for the shifter mechanism based on the position information and distance information obtained by said measuring and a predetermined trip distance information; processing the shifter mechanism according to the position information of the bimetals; installing the processed shifter mechanism at the determined installing position; and determining a graduation position of a trip operation current value by converting a difference between a predetermined allowable trip operation time and a test-operated trip operation time into a rotation angle.