Adjustable circuit breaker thermal trip unit.

摘要

Apparatus for adjusting the calibration of a thermal trip unit (2) which is to be used in conjunction with an electrical circuit breaker. A rotatable knob (74) is provided which adjusts the trip unit (2) to between one hundred percent of the rating of the circuit breaker and some value which is less than one hundred percent. An adjustable stop screw (84) is provided to engage the rotatable knob (74) when the knob (74) is rotated to adjust the oalibration of the trip unit to the desired value which is less than one hundred percent of the rating of the breaker. The adjustable stop screw (84) thereby limits travel of the adjustable knob between only one hundred percent of the rating of the circuit breaker and the desired value which is less than one hundred percent.