Abstract: In one aspect, the present invention provides an electromagnetic circuit interrupter for use in a high voltage direct current (DC) aircraft power distribution system. The electromagnetic circuit interrupter comprises a contact mechanism operable to separate first and second electrical contacts by a first predetermined distance d1 for a predetermined time ? so as to sustain an arc when the contact mechanism is opened. The contact mechanism is further operable to separate the first and second electrical contacts by a second predetermined distance d2 after the predetermined time ? so as to extinguish the arc. The first predetermined distance d1 is less than said second predetermined distance d2. By deliberately sustaining the arc for a relatively long period of time, this aspect of the present invention is particularly useful for extending the operational lifetime of the contacts and thereby of the electromagnetic circuit interrupter itself.

Abstract: A non-homogeneous cam includes an eccentric disk having side surfaces with an opening therethrough, and a cam surface disposed between the side surfaces. A first radius extending from a point within the opening to a number of first portions of the cam surface and second radii extending from the point to second portions of the cam surface define the cam surface. The first radius is greater than each of the second radii. The cam surface includes a first cam surface generally having the first radius and a second cam surface having a plurality of the second radii. The first and second cam surfaces define an angle of less than 90 degrees. The eccentric disk is generally made of a first material having a first strength. A portion of the eccentric disk between the first and second cam surfaces is made of a different second material having a greater second strength.

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: This publication discloses a switching device combination for capacitive loads (3) connected to a direct voltage. The switching device combination includes an actual switch component (1) for connecting voltage to the capacitive load (3), a charging switch component (2) for connecting charging voltage to the capacitive load in the initial stage, which charging switch component is dimensioned for a lower current than the actual switch component (1), a controller component (4), by means of which the actual switch component (1) is controlled from an open state to a closed state and vice versa, with the aid of a mechanical lever (5), which is connected to a first shaft (6), and delay elements (11) for delaying the connection of the actual switch component (1), so that the closed charging switch component (2) will have time to charge the capacitive load (3) before the connection of the actual switch component (1).

Abstract: A circuit breaker control system includes a motor driven fork assembly, activated from a remote location, for simultaneously opening all of the breaker load contacts and locking them in an open condition. A DC voltage is selectively applied to energize the reversible DC motor. The switch at the remote location can be operated to enable a user-customer to return the breaker to operable condition at the breaker site. This is accomplished with an SCR circuit that is enabled by the remote switch and actuated by the user to operate the motor in a reverse direction to release the load contacts.

Abstract: A driver mechanism for a dot matrix printhead, including an electromagnet, an armature, and a print impact element connected to the armature by a cantilever spring, energization of the electromagnet and consequent movement of the armature to closed position driving the impact element to impact a record sheet supported on a platen; a concentrated mass load is mounted on the spring, sufficient to maintain the impact element essentially in its rest position during a substantial portion of the armature movement so that the force/travel characteristic of the spring governs movement of the impact element, with maximum force at the outset and near zero or zero force at impact. Energization of the electromagnet is interrupted when the armature closes, and a shunt circuit holds the armature closed until just before impact.

Abstract: An improved movement for a time delay relay cooperates with an electromagnet and a timer to provide either "On Delay" or "Off Delay" operation of the relay contacts. The movement has an elongated operating plunger that is movable in forward and backward strokes, a latch, and a contact actuator coupling the latch to the relay contacts. A pair of springs are disposed in a spring cage formed in the actuator and at least one spring-compressing flange is carried by the plunger and disposed between the springs. In the on delay mode of operation, one spring is loaded against the actuator upon a forward stroke of the plunger. In the off delay mode of operation, the other spring is loaded against the actuator upon a backward stroke of the plunger. The latch is restrained upon the movement of the plunger to load one of the springs, and is subsequently released from its restraint after a time delay to operate the relay contacts with spring action.