Abstract: A solenoid assembly for a circuit breaker having a clapper with an increased mass is provided. The mass, preferably at least one non-ferrous slug, increases the mass of the clapper so that the solenoid response time is slowed. That is, the added mass creates an inertial delay that slows the solenoid clapper as the clapper moves between the first position and the second position. Preferably, the delay is between 48 ms and 60 ms, and more preferably 50 ms. The clapper having a non-ferrous slug may also be incorporated into existing circuit breakers by, for example, coupling the non-ferrous slug to the preexisting clapper, or replacing the clapper with a clapper assembly having at least one non-ferrous slug thereon.

Abstract: A parallel pole magnetohydraulic circuit breaker (10), having a single trip element (271) and a pair of trip mechanisms (101, 102), achieving an increased current carrying capacity with reduced nuisance trips. The tip mechanisms (101, 102) are contained within separate housings (14, 16), with electrical connections (30, 40) and multipole trip mechanism (101, 102) communicating through apertures in the common wall (14′). Preferably, the armature (260) of the trip element (271) acts on a single trip mechanism (101, 102), which multiplies the available force to trigger a trip of the other tip mechanism.

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 electromagnetic circuit breaker has a housing that includes a separately defined arc chamber in which the moving contact travels as the breaker is tripped, and the chamber has a divergent shape to facilitate exhausting the hot gases from the arc chamber through a metal screen and through vent openings in the end wall of the breaker housing. The housing is made in two half sections that are held together by rivets and the location of one of these rivets is isolated from the fixed contact at the lower end of the arc chamber by the unique arc chamber configuration. The lower wall of the circuit breaker housing is adapted to receive either a molded switch subassembly or to receive a terminal strip that is held in place by the primary terminals of the breaker and is adapted also to support auxiliary terminals that operate a shunt coil. The shunt coil itself is fitted on a bobbin that is selectively mounted on the bobbin that contains the primary electromagnetic coil for the breaker.

Abstract: Improvement in a circuit breaker employing a fixed pole piece associated with a movable magnetic core within a tube containing damping fluid wherein the side walls of the tube are transparent in order to facilitate the inspection of internal components. Calibrations can be provided on the side walls as well. Additionally, the tube is preferably made of resinous materials which is heat sealable to the end cap carrying the pole piece to which the breaker tripping armature is attracted by overload sensed by a coil surrounding the movable core and upon overload causing the armature to move to the pole piece and open the circuit breaker contact.

Abstract: The invention relates to a control device for a circuit breaker. The circuit breaker is controlled mechanically by an engagement spring (8), by a disengagement spring (2), and by a hydraulic transmission for transmitting a portion of the energy in the engagement spring to the disengagement spring. The device has circular symmetry about a longitudinal axis.

Abstract: A circuit breaker includes a tripping device in which a magnetic core is contained in a vessel of viscous fluid in a magnetic frame. An armature is disposed adjacent the core and is connected to a toggle mechanism. Under conditions of moderate overloads, the armature and the core ineract and the tripping device provides a time delay before it operates. Under severe fault conditions the armature is activated directly and the effect of the core is of less significance. The core or the armature are tapered, to provide a desired balance between the delayed and instantaneous operating characteristics.

Abstract: A circuit protecting sensor comprises a cylinder divided into two cylinder members with a common magnetic head interposed between them, one of which members contains a viscous fluid sealed therein and an oil plunger and the other member contains an operating plunger projecting partly out of the cylinder, and the respective plungers are biased by a spring normally away from the magnetic head. When a short-circuit current is detected by a coil wound on the cylinder, the operating plunger is immediately attracted by the magnetic head independently of the oil plunger prior to its attraction to the magnetic head.

Abstract: A high performance, manually and automatically operable, trip-free magnetic circuit breaker incorporates a magnetic actuation system with improved core, clapper and coil mounting to achieve more accurate and consistent breaker operation; incorporates a modular structure permitting adaptation of the breaker for use in a variety of breaker applications while minimizing circuit breaker costs; and incorporates improved magnetic circuit means to achieve more reliable breaker operation in flux switch type breaker applications.