Abstract: A circuit breaker mechanism comprises a line terminal, a load terminal and a set of contacts between the terminals. A fixed contact is connected to the line terminal, and a moving contact is connected to the load terminal via a conductive frame and a load sensing element. The moving contact is fixed to a contact carrier which is supported pivotably on conductive pins which are electrically connected to the frame. A spring urges the contact carrier into snug engagement with the conductive pins. The arrangement obviates the need for a flexible conductive pig-tail to form a current path between the contact carrier and the frame, simplifying the construction and improving the performance of the circuit breaker. With this arrangement, the current path extends from the line terminal to the moving contact, through the contact carrier, through the conductive pins, to the conductive frame and through the load sensing element to the load terminal.

Abstract: A circuit breaker mechanism comprises a line terminal, a load terminal and a set of contacts between the terminals. A fixed contact is connected to the line terminal, and a moving contact is connected to the load terminal via a conductive frame and a load sensing element. The moving contact is fixed to a contact carrier which is supported pivotably on conductive pins which are electrically connected to the frame. A spring urges the contact carrier into snug engagement with the conductive pins. The arrangement obviates the need for a flexible conductive pig-tail between the contact carrier and the frame, simplifying the construction and improving the performance of the circuit breaker.

Abstract: A circuit breaker mechanism comprises a coil which surrounds a tube in which a magnetic core can move against the urging of a spring. An armature is located adjacent the coil and moves transversely relative to the axis of the coil, with a head portion of the armature being attracted towards a pole piece of the mechanism, while a foot portion of the armature is attracted to the magnetic core. The armature is pivoted to a magnetic frame at a point between the head and foot portions, so that the magnetic force between the head portion and the pole piece is counteracted to some extent by the magnetic force between the foot portion and the magnetic core. This in turn depends on the position of the magnetic core in the tube, and the setting of an adjuster mechanism which spaces the foot portion closer to or further away from the core in use. The adjuster mechanism allows the instantaneous tripping characteristic of the mechanism to be adjusted in use.

Abstract: A circuit breaker mechanism comprises a coil which surrounds a tube in which a magnetic core can move against the urging of a spring. An armature is located adjacent the coil and moves transversely relative to the axis of the coil, with a head portion of the armature being attracted towards a pole piece of the mechanism, while a foot portion of the armature is attracted to the magnetic core. The armature is pivoted to a magnetic frame at a point between the head and foot portions, so that the magnetic force between the head portion and the pole piece is counteracted to some extent by the magnetic force between the foot portion and the magnetic core. This in turn depends on the position of the magnetic core in the tube, and the setting of an adjuster mechanism which spaces the foot portion closer to or further away from the core in use. The adjuster mechanism allows the instantaneous tripping characteristic of the mechanism to be adjusted in use.

Abstract: An electro-magnetic operating device 10 for a circuit breaker includes a coil 12 defining a cavity 14. A stator frame 20 which includes a pole piece 18 is arranged about the coil 12. A tube, which is closed off at one end by an end wall and at an opposed end by the pole piece 18 is arranged in the cavity 14. The tube 24 carries a core 22 therein. The plunger 22 is urged away from the pole piece 18 by a coil spring 28 arranged in the tube 26. The spring 28 is selected so that, when a load current of 100% is carried in the coil 12, the electro-magnetic force imparted to the core 18 exceeds the spring force imparted by the spring 28 to the core 22.

Abstract: A circuit breaker 10 includes a housing and an operating mechanism 12 contained within the housing. An indicating arrangement is carried by the operating mechanism 12 and is displaceable relative to the housing under the action of the operating mechanism 12 for indicating the status of the operating mechanism 12.

Abstract: An electro-magnetic operating device 10 for a circuit breaker includes a coil 12 which defines a cavity 14. A pair of elements 34, 44 are slidably arranged within the cavity 14, a first element 34 being operable to cause a time delay tripping of the circuit breaker and a second element 34 being operable to cause a substantially instantaneous tripping of the circuit breaker. A first pole piece 22 is associated with the first element. A linkage 64 is carried by the second element 44 for linking the second element to a moving contact carrier 66 of the circuit breaker. A frame 18, which defines a magnetic path, is arranged about at least a part of the coil 12, the magnetic frame 18 defining a second pole piece 40 which is aligned with the first pole piece 22. The first pole piece 22 and the elements 34, 44 are displaceable towards the second pole piece 40 to effect tripping of the circuit breaker.

Abstract: A ground fault interrupter 10 includes a core 12. Two load current-carrying wires 14, 16 pass through the core 12. A primary coil 44 is carried on the core 12 for sensing a current imbalance in the wires 14, 16. An auxiliary coil 18 is wound on the core 12. A pair of back-to-back zener diodes 20 is connected in series with the coil 18 to supply current to the coil 18 when an applied voltage exceeds a predetermined value between wires 14 and 16 or between either one of the and ground.

Abstract: A shunt trip device includes an armature 18 pivotally mounted on a frame 12 of a ferro-magnetic material. A "U"-shaped member 20 is mounted on the frame 12 via a spacer 30 of a non-magnetic material. The member 20 and a portion of a post 16 of the frame 12 and the armature 18 define a first magnetic circuit. A limb 22 and a bridge portion 26 of the member 20 together with a part 14.1 and the post 16 of the frame and the armature 18 define a second magnetic circuit. A limb 24 and the bridge 26 of the member 20 together with the part 14.1 and the post 16 of the frame 12 and that portion of the armature 18 between the post 16 and the limb 24 define a third magnetic circuit. A coil 34 is carried on the limb 22 of the member 20 and permanent magnetic 22 is sandwiched between the portion 26 of the member 20 and the part 14.1 of the frame 12.

Abstract: An electro-magnetically operable device 12 for a circuit breaker 10 comprises a coil 13 that defines a cavity. A first plunger 14 and a second plunger 16 are located within the cavity, adjacent one another. The first plunger 14 is housed in a sealed canister 18 which is filled with a damping liquid. The plunger 14 is displaceable within the canister 18 in a damped manner. The second plunger 16 is also displaceable within the cavity and movement thereof is guided by an open tube 20. The first plunger 14 and the second plunger 16 are urged away from a pole piece 30 of the device 12 via helical springs 32 and 34, respectively.

Abstract: A current monitoring assembly 12 of a circuit breaker includes a coil 16, a tube 18 slidably mounted in the coil 16, a core 20 slidably housed within the tube 18, a first pole piece 22 mounted on an end of the tube 18 and an "O"-shaped magnetic frame 24 having a second pole piece 26 aligned with the first pole piece 22. A retarding fluid is contained within the tube 18 and a core spring 46 is arranged intermediate an end of the core 20 and the pole piece 22.

Abstract: An electro-magnetic shunt trip device has a pair of aligned plungers 10,24. A first plunger 19 acts on an operating member 20 which is pivotal and connected to a spring 18. The second plunger 24 is manually displaceable. A further spring 26 is located between the plungers. The plungers are part of a magnetic circuit, with a magnetic field being generated by a permanent magnet 30 and an electro-magnet 32. The permanent magnet and the electro-magnet generate fields of opposite polarity. If there is no current in the electro-magnet, the field provided by the electro-magnet will be sufficiently strong to hold the two plungers together. The spring 18 acting on the operating member will cause it and the plungers to move, so that the operating member is in a non-tripping position.

Abstract: A circuit breaker mechanism has an armature component that is slidably displaceable between latched and tripping positions. The armature is connected to a moving contact carrier that is pivotally connected to an operating handle that is also pivotal. The armature is connected to the carrier by a spring. The armature has a latching formation which engages a projection. When tripped,the armature is slightly pivoted to clear the projection.

Abstract: A molded case circuit breaker includes a manually resettable undervoltage trip mechanism for initiating a trip operation of the circuit breaker upon an undervoltage condition. The undervoltage trip mechanism includes a solenoid having a fixed electrical coil surrounding a pair of separable movable ferromagnetic plungers. Disposed between and captured by the two plungers is a compression spring for physically separating the two plungers upon the occurrence of an undervoltage condition. Upon such an undervoltage condition, one of the plungers is positioned to engage and rotate a trip lever for initiating a trip operation of the circuit breaker. The other plunger is secured to an elongated manually depressible reset button that extends through the molded case of the circuit breaker. After a trip operation, the reset button can be depressed to reestablish physical engagement between the first and second plungers, enabling the circuit breaker to be reset.

Abstract: A molded case circuit breaker includes a manually resettable undervoltage trip mechanism for initiating a trip operation of the circuit breaker upon an undervoltage condition. The undervoltage trip mechanism includes a solenoid having a fixed electrical coil surrounding a pair of separable movable ferromagnetic plungers. Disposed between and captured by the two plungers is a compression spring for physically separating the two plungers upon the occurrence of an undervoltage condition. Upon such an undervoltage condition, one of the plungers is positioned to engage and rotate a trip lever for initiating a trip operation of the circuit breaker. The other plunger is secured to an elongated manually depressible reset button that extends through the molded case of the circuit breaker. After a trip operation, the reset button can be depressed to reestablish physical engagement between the first and second plungers, enabling the circuit breaker to be reset.

Abstract: A circuit breaker comprises improved thermal and electromagnetic trip means comprising a currrent carrying bimetal operable upon the occurrence of lesser overloads to effect time-delay thermal tripping operations, and electromagnetic means energized by the current in said bimetal which electromagnetic means is operable upon the occurrence of more severe overloads to effect instantaneous electromagnetic tripping operations.