Abstract: A molded-case circuit breaker having an undervoltage release device housed therein is provided with a flexible molded double ended lever for resetting the undervoltage release device and a torsion spring braced upon the two arms of the lever so as to minimize the effects of stress and creep on the molded members when manually actuating repeatedly to reset the undervoltage release device against the biasing spring of the device.

Abstract: Apparatus for adjusting the calibration of a thermal trip unit which is to be used in conjunction with an electrical circuit breaker. A rotatable knob is provided which adjusts the trip unit 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 is provided to engage the rotatable knob when the knob is rotated to adjust the calibration 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 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.

Abstract: A multiple pole circuit breaker comprises stationary and movable contacts in each pole, with a cross bar extending between the poles and causing concerted movement of the movable contacts. An operating mechanism effects movement of the movable contacts between open and closed positions, and a resettable undervoltage release mechanism cooperates with the operating mechanism to effect movement of the movable contacts. The undervoltage release mechanism operates to move the movable contacts from the closed to open position upon the occurrence of voltage levels less than a predetermined value, with the undervoltage release mechanism being reset by physical contact with the cross bar as the cross bar moves with the movable contacts from the closed to open positions.