Abstract: A molded case current limiting circuit interrupter includes a pair of pivoting contact arms each supporting a contact and being connected to wiring terminals such that current flows through the contact arms in opposite directions. One of the contact arms has a movable pivot point. A magnetic drive slot motor device is provided to generate electrodynamic contact opening force upon the contact arms during short circuit conditions. A high-speed magnetic trip device releases the operating mechanism under short circuit conditions to move the arm pivot point before the contact arms reclose. A spring latch may be provided to latch the upper contact arm in a contact-separated position during short circuit conditions until such time as the overcurrent flow through the breaker operates a thermal and magnetic trip mechanism to move an operating mechanism to the tripped position.

Abstract: A current limiting circuit breaker includes two parallel pivoting contact arms carrying contacts at the ends thereof. The upper arm is double pivoted and is operated by a mechanism between open and closed positions. A magnetic drive slot motor device surrounds the lower arm and operates during extreme overcurrent conditions to draw the lower arm down and aid in rapidly separating the contacts. An arm positioning assembly is spring loaded to bias the lower arm toward a closed circuit position and provide contact closing force, the upper limit of travel being set by a rod extending through the end of the lower contact arm to abut against the slot motor.

Abstract: A current limiting circuit breaker comprises an improved slot motor magnetic drive device. The threshold level of overload current which produces current limiting action is raised, yet the degree of current limiting action during high overload currents is maintained by placing a thin saturable magnetic steel plate across the open end of the slot motor magnetic drive device. During overcurrent conditions below the threshold value, the plate shunts most of the magnetic flux and prevents production of magnetodynamic force upon the contact arm. Above the threshold level, the overcurrent generates magnetic flux sufficient to saturate the plate and forces additional flux into the air gap where the flux interacts with the contact arm to drive the contact arm into the slot and produce current limiting action in a normal manner.

Abstract: A circuit breaker comprises a stored-energy mechanism and a resettable roller-type latch for latching the stored-energy mechanism. The latch is operable upon the occurrence of overload current conditions to release the stored-energy mechanism to thereby trip the breaker. Alternately the latch may be actuated by utilizing a separate switch.

Abstract: A circuit breaker comprises a stored energy mechanism and a solid state overcurrent sensing trip circuit. The circuit breaker also includes a remotely operable shunt trip device having a zener diode for operation from high voltage control circuits without the necessity for a stepdown transformer.

Abstract: A circuit breaker including a solid-state circuit for providing regulated current to operate a holding coil for an undervoltage release mechanism. An alternating current control line feeds a full wave bridge rectifier in the control circuit to provide pulsating direct current to a reference voltage supply circuit, a current regulating circuit, and the holding coil of an undervoltage release mechanism. The current regulating circuit comprises two series connected units of an integrated circuit quad current differential operational amplifier. The output of the second unit controls the base current of a regulating transistor which is series connected to the holding coil. The reference voltage supply circuit includes a transistor connected as a variable resistor to provide operation of the circuit over a wide range of input voltages without excessive heat generation.

Abstract: A multipole circuit breaker including a trip release actuator having a single coil coaxially surrounding a plunger and mounted within a hollow cylindrical actuator support frame. The actuator is mounted in association with a latch mechanism and includes a spring biasing the plunger toward release of the latch mechanism. The coil is responsive to an electronic sensing and control circuit and serves, when energized, to oppose the action of the bias spring and maintain the plunger in a position to prevent release of the latch mechanism during normal conditions. Upon either undervoltage or overcurrent conditions the sensing and control circuit deenergizes the coil, allowing the bias spring to move the plunger into engagement with the latch mechanism, effecting release of the latch mechanism and separation of the circuit breaker contacts.

Abstract: A multipole circuit breaker including a latch release actuator having a trip coil and a hold-in coil coaxially surrounding a plunger and mounted within a hollow cylindrical actuator support frame. The actuator is mounted in association with a latch mechanism and includes a spring biasing the plunger toward release of the latch mechanism. The hold-in coil is responsive to voltage conditions on an external control line and serves to oppose the action of the bias spring and maintain the plunger in a position to prevent release of the latch mechanism when the voltage on the control line is above a predetermined level.