Abstract: A current sensing transformer useful for sensing overload current with static trip units is fabricated from an inexpensive array of transformer core laminations and a conventional secondary transformer winding. The transformer primary strap is arranged about the secondary winding for improved flux transfer.

Abstract: A flux shifting circuit breaker trip device is disclosed which includes a permanent magnet for retaining a solenoid armature in opposition to a spring force. Energization of the solenoid winding produces a magnetic flux in opposition to the permanent magnet flux to extend the armature under the spring force. In order to provide ambient temperature response, the solenoid armature is formed from a stem part and a barrel part held together by a meltable material. Increase in ambient temperature above a predetermined value causes the material to melt allowing the stem part to extend under the spring force to trip the breaker.

Abstract: A fully automated residential-type circuit breaker assembly is made possible by the provision of retaining slots and guide channels formed within the breaker case. The breaker case then serves as an assembly fixture for specially designed armatures and magnets used within the trip section of the breaker as well as for a special designed bi-metallic trip element. A high calibration yield is accomplished by means of a low friction latch assembly.

Abstract: A low inductance resistor for high current limitation is arranged from a single conductor wrapped in a continuous direction to form a plurality of turns wherein current transport through each of the turns induces a corresponding magnetic field to oppose the magnetic field induced within each next adjacent turn. The resistor finds application within a current limiter unit which employs magnetic repulsion and gas pressure to direct arcs that occur between separating contacts to within the high voltage region of an arc chute. The resistor is connected across the arc to reduce the arc current to a low enough value so that the arc becomes extinguished within a predetermined period of time.

Abstract: A fully automated residential-type circuit breaker assembly is made possible by the provision of retaining slots and guide channels formed within the breaker case. The breaker case then serves as an assembly fixture for specially designed armatures and magnets used within the trip section of the breaker as well as for a special designed bi-metallic trip element. A high calibration yield is accomplished by means of a low friction latch assembly.

Abstract: A shield assembly for isolating line and load stabs within a circuit breaker compartment when the circuit breaker is removed from the compartment. The assembly consists of a pair of separately hinged shields interconnected by a link which terminates in a moveable pin. The pin is captured in a first slot within the assembly actuator arm and in a second slot within a supportive side frame. Movement of the actuator arm in a first direction causes the connecting link pin to move within the first slot to open the shields. Return of the actuator arm in an opposite direction causes the connecting link pin to travel within the second slot in an opposite direction to close the shields. The shield assembly contains actuating mechanisms at both sides of the breaker compartment in order to defeat any attempt by an operator to open the shields with the breaker withdrawn from the compartment.

Abstract: A slideably mounted insulating shield is positioned over the terminals of a secondary disconnect attached to the side wall of a circuit breaker compartment. Inserting the circuit breaker into the compartment brings the secondary disconnect terminals on the breaker into engagement with the secondary disconnect terminals in the compartment by displacing the insulating shield. Removal of the breaker from the compartment forces the insulating shield to return to position over the compartment secondary disconnect terminals thereby isolating the disconnect terminals from inadvertent contact with an operator.

Abstract: A compact and economic shield mechanism is used within circuit breaker compartments where a minimum separation distance exists between the end of the circuit breaker and the end of the compartment when the circuit breaker is first inserted within the compartment. The combination of an actuating lever and an extension spring converts the motion of the circuit breaker into a linear force sufficient to rapidly open the line and load shields within the minimum distance travelled by the breaker. The compartment line and load shields return to their closed position under a restoring force provided by the combination of a linear spring and a torsion spring when the breaker is withdrawn from the compartment.