Abstract: A spring-loaded cam electrical connector is used to rapidly connect circuit breaker load terminal straps with the associated electric distribution system wire conductors. Rotation of the cam in one direction traps the end of the wire conductor between the bottom of the cam support and the circuit breaker load terminal strap to make the electrical connection while rotation of the cam in the opposite direction releases the end of the wire conductor to break the electrical connection.

Abstract: An electronic circuit interrupter is protected against thermal damage upon loosening of the lug connectors that connect the circuit interrupter with the load circuit. Thermal sensing elements attached to the lugs connect with the circuit interrupter trip unit to initiate circuit interruption when the temperature sensed exceeds a predetermined value.

Abstract: A spring-loaded cam electrical connector is used to rapidly connect circuit breaker load terminal straps with the associated electric distribution system wire conductors. Rotation of the cam in one direction traps the end of the wire conductor between the bottom of the cam support and the circuit breaker load terminal strap to make the electrical connection while rotation of the cam in the opposite direction releases the end of the wire conductor to break the electrical connection.

Abstract: An arc isolation shield for molded case circuit breakers is inserted between the circuit breaker case and cover and attached to one leg of the operating cradle. The knee of the circuit breaker moveable contact arm contacts the bottom of the shield and moves the shield in unison with the contact arm to protect the contact arm, contact braid and operating spring upon contact separation under severe overcurrent conditions.

Abstract: Molded case circuit breaker accessories using slightly modified circuit breaker cases are described. Several of the accessories utilize a microswitch to provide remote indication of an auxiliary function. One modification of the circuit breaker case includes upstanding posts to capture and position the microswitch while a further modification utilizes the magnetic trip unit adjustment screw and a support plate.

Abstract: An electric circuit breaker operating mechanism includes an insulated armature latch which prevents deleterious arc formation between the operating mechanism cradle and the armature latch surface when the circuit breaker contacts are separated under overcurrent circuit conditions. The insulated armature latch carries a tolerance take-up spring which interacts between the operating mechanism cradle and the circuit breaker trip bar assembly to insure free travel of the operating cradle during contact separation.

Abstract: A molded case circuit breaker for residential use employs an additional safety feature to ensure a fail-safe condition in the event that the circuit breaker is installed within a circuit that may be subjected to an excessive over-current fault that disables the circuit breaker trip unit. The integral bimetal-fuse within the circuit breaker trip unit responds to interrupt circuit current before any damage can occur to the associated electrical wiring system.

Abstract: A molded case thermal-magnetic circuit breaker having improved low current magnetic trip response pivotally arranges the magnet within the circuit breaker thermal-magnetic trip system for controllably moving toward the latching armature assembly. The movement of the magnet decreases the magnetic separation distance between the magnet and the latching armature to optimize the magnetic trip forces and thereby enhance low current magnetic trip response.

Abstract: A circuit breaker latch assembly eliminates the need for polishing the opposing latch surfaces to reduce static surface friction and lower the latching force. The end of the circuit breaker cradle operator is offset relative to the restraining surface of the armature-latch to reduce the static friction that must be overcome to move the armature-latch away from the cradle operator. Subsequent release of the cradle operator then allows the circuit breaker operating mechanism to separate the circuit breaker contacts upon the occurrence of predetermined overload current conditions.

Abstract: An arc gas controller-insert is used with molded case circuit breaker covers to direct the flow of arc gases that occur during intense overcurrent circuit interruption. The gas controller-insert provides access to the line and load terminal lugs for connection with and disconnection from an associated electrical power distribution system while controlling the egress of the arc gases.

Abstract: A molded case thermal-magnetic circuit breaker having improved low current magnetic trip response pivotally arranges the magnet within the circuit breaker thermal-magnetic trip system for controllably moving toward the latching armature assembly. The movement of the magnet decreases the magnetic separation distance between the magnet and the latching armature to optimize the magnetic trip forces and thereby enhance low current magnetic trip response.

Abstract: An arc gas controller-insert is used with molded case circuit breaker covers to direct the flow of arc gases that occur during intense overcurrent circuit interruption. The gas controller-insert provides access to the line and load terminal lugs for connection with and disconnection from an associated electrical power distribution system while controlling the egress of the arc gases.

Abstract: A molded case circuit interrupter of the type employing a thermal-magnetic trip unit to interrupt circuit current utilizes a flexible electrical braid conductor to connect between the thermal-magnetic trip unit and the movable contact arm. A helical spring arranged around the braid conductor at the welded connection with the movable contact arm provides long-term strain relief. A metal phosphate coating on the surface of the circuit breaker operating cradle and latch assembly eliminates polishing while insuring release of the cradle from the cradle-latch interface surfaces.

Abstract: A compact circuit breaker containing an electronic trip unit for interrupting overcurrent conditions within a protected circuit is made operable over a wide operating current range by means of current transformers having multiple turn primary windings. The primary windings are selected to provide a constant ampere-turns ratio to the current transformers without changing the size of the secondary winding or the volume of the transformer core.

Abstract: A compact circuit breaker utilizing an electronic trip unit for overcurrent determination contains a compact slot motor and a compact arc chute to minimize and control the arc that occurs when the circuit breaker fixed and movable contacts become separated upon intense overcurrent conditions. The fixed contact is arranged on a fixed contact arm that includes an arc runner for rapidly directing the arc into the arc chute. The arc chute includes a keying arrangement which cooperates with slots formed within the circuit breaker case interior sidewalls to orient the arc plates relative to the arc runner.

Abstract: A compact current limiting circuit breaker with an electronic trip unit arranged within the circuit breaker cover and current transformers in the circuit breaker case incorporates reinforcement ribs in the cover to provide added strength. The cover also includes line terminal plugs that removably attach to the cover for preventing inadvertent access to the circuit breaker line terminals when the circuit breaker is energized. Protrusions formed on the bottom surface of the circuit breaker cover under the trip unit provide further strength while cooperating with flexible pads on the top of the current transformers to automatically compensate for manufacturing tolerances.

Abstract: A combined arc gas controller-line terminal plug is used within molded case circuit breaker covers to direct the flow of arc gases that occur during intense overcurrent circuit interruption. The plugs simultaneously prevent access to the line terminal lugs while controlling the egress of the arc gases. Moreover, the plugs are removable for connection with and disconnection from an associated electrical power distribution system.

Abstract: A circuit breaker enclosure consists of a cover and a case designed for robotic assembly of the circuit breaker components. A current transformer assembly and a printed wire board containing the electronic trip unit circuit are precisely positioned within the case and cover by means of a transitory circuit breaker case support platform. The transitory support platform includes four upstanding posts that pass through openings formed in the circuit breaker case and are received within corresponding openings through the circuit breaker cover. Leads extending from the current transformer assembly within the case become automatically positioned within corresponding openings through the printed wire board by means of tapered lead-in openings formed within the circuit breaker cover.

Abstract: A circuit breaker enclosure consists of a cover and a case designed for robotic assembly of the circuit breaker components. A current transformer assembly and a printed wire board containing the electronic trip unit circuit are precisely positioned within the case and cover by means of a transitory circuit breaker case support platform. The transitory support platform includes four upstanding posts that pass through openings formed in the circuit breaker case and are received within corresponding openings through the circuit breaker cover. Leads extending from the current transformer assembly within the case become automatically positioned within corresponding openings through the printed wire board by means of tapered lead-in openings formed within the circuit breaker cover.

Abstract: Line and load lugs are fixedly attached to each pole of a multi-pole molded case circuit breaker without requiring screws. The lugs are positioned within the line and load lug compartments at opposing ends of the breaker by grooves formed along the sides of the lugs and rails formed within the internal surfaces of the compartments. A lug support cap fitted to the bottom of each line and load lug interacts with detents formed on the inner surfaces of the compartments to securely retain the line and load lugs within the compartments.