Abstract: An electrically isolated rotor assembly for a cassette assembly of a circuit breaker includes a rotor having a first side and an opposing second side, a first isolation cap disposed on the first side, a second isolation cap disposed on the second side. Each isolation cap preferably includes a centrally located knob with a bushing surrounding each knob, wherein the bushings are sized for securement within apertures within first and second cassette half pieces.

Abstract: A circuit breaker includes an upper rail mounting device defined by a line terminal having a pair of spaced-apart jaws. A bimetal is adjusted by means of a calibration screw. An aperture is provided in an upper sidewall portion of a base of the circuit breaker for access to the calibration screw by a calibration device. The aperture is positioned so that the calibration device must pass through the jaws of the upper rail mounting device. This ensures that the calibration screw can only be operated when the circuit breaker is disconnected from an electrical supply.

Abstract: In an exemplary embodiment of the invention, a calibration arrangement and process for use in a circuit protective device are presented. An exemplary calibration assembly for use in the calibration process of the present invention includes a split clamp arm having a first opening for receiving and holding a calibration pin and a second opening for receiving an actuator key. A portion of the split clamp arm is divided into a first arm and a second arm by a channel which extends from a first end of the split clamp arm through the first opening and communicates with the second opening. The split clamp arm is opened by inserting the actuator key through the second opening and because of the preferred oblong or rectangular shape of the second opening of the split clamp arm, rotation of the actuator key therein forces the members forming the first opening of the split clamp arm apart from one another.

Abstract: Thermal triggering apparatus, for a protection device featuring an electrically conductive bimetallic strip and a plate of thickness (e) which supports the bimetallic strip. The bimetallic strip has a first end free that is capable of deforming and a second end or foot which is fitted into a cavity in the plate characterised in that the foot of the bimetallic strip passes through the cavity so that it protrudes below the bottom face of the plate by a length (a) that easily exceeds the thickness (e) of the plate, and the protruding part of the foot has an electrical connection point linked to a conductive part so as to form the direct heating element of the bimetallic strip.

Abstract: A thermal overload relay comprising a change-over spring mechanism and a contact mechanism that is separated from the spring mechanism. The contact mechanism is actuated by the spring mechanism, which is driven by a bimetallic strip when an overcurrent flows through the strip. The spring mechanism has no electrically conducting portion. The change-over point of the spring mechanism varies only a little, thus enhancing the reliability. The spring mechanism is easy to assemble and adjust.

Abstract: A multi-pole circuit interrupter comprising an electrically insulating housing having two side walls and at least two partition walls defining therebetween a central compartment and at least two side compartments. A central pole unit is disposed within the central compartment and a side pole unit is disposed within each of two side compartments. Each of the units includes a stationary contact element, a movable contact arm, an arc extinguisher and terminals for the external connection. The distance between a center line passing through the centers of the stationary contact element, the movable contact arm and the arc extinguisher of each of the pole units is smaller than the distance between the center lines passing through the terminals of each pole unit, so that the thickness of the housing side wall can be increased without increasing the overall width dimension of the housing.

Abstract: A multipole low-voltage circuit breaker with an insulating material housing and arc quenching chambers. By a new mechanical design, the installation of the arc quenching devices is to be facilitated. All arc quenching chambers of a switchgear are arranged in a quenching chamber housing which is subdivided by partitions and is fastened to the insulating material housing of a circuit breaker. The quenching baffles are fastened directly to the walls of the arc quenching chambers. A low-voltage circuit breaker with an insulating material housing of compact design is thus provided.

Abstract: In an overcurrent protective relay thermally operable by a bimetal, a movable contact mechanism is employed by utilizing a snap inversion mechanism. A normally-closed contact is employed with having an overtravel to achieve the reliable contacting. A manually resettable lever is also employed to open the normally-closed contact after the overcurrent protective relay has been actuated.

Abstract: A thermally-sensitive overcurrent protective relay includes a housing case, a bimetal strip bendable in response to an operating current flowing through a control circuit of the overcurrent protective relay, and a movable contact biased by a spring to form a toggle mechanism operable in response to the bending action of the bimetal. A lever supporting bracket mechanically supports the movable contact at a fulcrum portion and electrically connects the movable contact to a terminal. The terminal is mounted in the housing case to conduct current to the control circuit through a contact spring for electrically connecting the lever supporting bracket. This lever supporting member includes a trip current adjusting mechanism adapted to be rotated at its end portion by turning an adjusting screw for adjustment of the operation current.

Abstract: A thermally-sensible overcurrent protective relay comprising a toggle mechanism operable in connection with the bending operation of a bimetal bendable in response to current flowing through a main circuit a normally-open contact having a normally-open fixed contact element and a normally-open movable contact element both formed by a resilient conductive thin plate having a contact portion at one end thereof a normally-closed contact having a normally-closed fixed contact element and a normally-closed movable contact element both formed by a resilient conductive thin plate having a contact portion at one end thereof, and a mechanism adapted to be selected to an automatic resetting position and a manual resetting position in such a manner as to contact one surface of the contact portion of the normally-open fixed contact element at one end of a changeover lever pivotally rotatable to displace the normally-open fixed contact element toward the normally-open movable contact element and retain the normally-open c

Abstract: A protection switch, or a circuit breaker, includes a bimetallic element provided with a heating winding to form a portion of a structural unit insertable into an upper housing part, said structural unit further including a carrier connected to the bimetallic unit and having a connecting terminal extending from the carrier. The structural unit also including a terminal element connected to the heating winding and having an arc runner continuation, as well as carrying a contact piece of the switch contact. Continuations are provided for positioning the structural unit in a housing, the continuations engaging into guide grooves rigidly provided in the housing. The terminal element, in the region of the contact piece, is pressed against the housing stop and the carrier includes a fork-like free end embracing a catch rib of the housing. The bimetallic element is correctly positioned upon insertion of the structural unit into the housing so that readjustment is not necessary.

Abstract: A circuit breaker has a metal frame (10) disposed on a base of a housing. A trip-bar (6) made of molded plastic of like material is rotatably held on the frame (10) by insertion of a trip-bar pin (15) into a center through-hole provided on the trip-bar, and pinchers (14,14) of the trip-bar (6) pinch the trip-bar pin by elasticity of the plastic material to hold the same in place with very little lateral play.

Abstract: In the thermal-type overload relay such a construction that a bimetallic strip deforms due to heat produced by an excessive amount of current to actuate a normally closed movable contact which constitutes a normally closed contact, and an operating rod is moved in a predetermined direction to thereby close a normally open contact comprising a normally open fixed contact and a normally open movable contact, there is provided a reset rod moving in the direction perpendicular to the operating rod so that when the reset rod is moved in the direction perpendicular to the operating rod, the normally open fixed contact are caused to move toward the normally open movable contact, whereby the normally open contact is returned to the original position, and the normally closed contact is also returned to the original position by a returning movement of the normally closed movable contact due to the returning movement of the operating rod.