Abstract: A current sensor includes at least three bus bars made of flat-plate-shaped conductors and an inverter, a plurality of cores in which a core is formed by stacking flat plates made of U-shaped magnetic bodies, and a detecting element arranged on the side of an opening portion of each of the cores for detecting the intensity of a magnetic field. An interval between the core and another bus bar that is adjacent to the bus bar inserted into the U groove of the core is ½ of the length of the opening portion in the spacing direction, and the tolerance of the gap is set to a value obtained by subtracting the value of 3/2 of the length of the opening portion in the spacing direction from the value of the interval between the bus bars that are adjacent to each other, with the gap as a median value.

Abstract: An electromagnetic contactor includes a contact mechanism including a pair of fixed contacts having fixed contact portions and interposed in a current conduction path, and a movable contact having a pair of movable contact portions capable of contacting to and separating from the pair of fixed contact portions. At least one of the pair of fixed contacts or the movable contact is formed in a shape to form magnetic fields generating Lorentz forces opposing electromagnetic repulsion forces generated in an opening direction between the fixed contact portions and the movable contact portions when current is conducted. External connection conductors are connected to external connection terminals of the fixed contacts, an attachment direction of fixed portions fixed to the external connection terminal of the fixed contacts is set to cross a current flow direction flowing through the movable contact.

Abstract: A circuit interrupter provides a conducting path between two conductors and interrupts the conducting path in response to overcurrent conditions in the conductors. The interrupter includes a magnetic core around which the conductors are disposed. Each conductor is electrically coupled to an arc runner and a spanner is biased into contact with the arc runners to compete a conducting path between the conductors. A secondary response mechanism is provided adjacent to the core and includes arms extending around the core and a magnetic body. In response to overcurrent conditions of a first magnitude the body of the secondary response mechanism is attracted to the core causing the arms to displace the spanner out of contact with the arc runners. In response to overcurrent conditions of a second magnitude, such as due to direct short circuits, the spanner is repelled rapidly to a non-conducting position and the secondary response mechanism is attracted to the core to hold the spanner in the non-conducting position.

Abstract: A ground fault indicator for a multi-phase power distribution system includes a split-core magnetic pole assembly having a gap within which is developed a magnetic flux representative of the vector sum of the currents in the individual phase conductors of the system. A magnetic reed switch positioned within the gap responds to the summation current in the gap to trip an indicating circuit in a remotely mounted indicating module in the event of a ground fault.

Abstract: In a power distribution system having a first conductor carrying a current I.sub.1 and a second conductor carrying a current I.sub.2, in the same direction as I.sub.1, a differential current detector sensing when .vertline.I.sub.1 -I.sub.2 .vertline. exceeds a predetermined level, I.sub.3. The detector comprises a ferromagnetic yoke having first and second parallel bores accommodating the first and second conductors respectively. The first and second bores are interconnected by a coplanar slot in the yoke which extends transversely therebetween. The yoke further includes a third bore disposed between the first and second bores and orthogonal thereto. A reed capsule switch having two mutually exclusive conductive states extends through the third bore and is responsive to the flux generated by the currents I.sub.1 and I.sub.2, such that when .vertline.I.sub.1 -I.sub.2 .vertline..ltoreq.I.sub.3 the reed switch exhibits one conductive state and when .vertline.I.sub.1 -I.sub.2 .vertline.>I.sub.

Abstract: The disclosed instantaneously tripping device includes a stationary iron core encircling a conductor and responsive to a flow of shortcircuiting current through the conductor to attract a movable iron core to open contacts. A locking and releasing plate are operatively coupled to the movable core to transfer the movement of a closing latch to the latter. After the completion of the closing operation effected by a switching mechanism, the locking plate locks the movable core while only during the closing operation of the switching mechanism does the releasing plate release the movable core to permit it to be attracted by the stationary core.