Abstract: A measuring assembly is formed by association of a current sensor with non-magnetic toroid and a supply transformer with magnetic circuit arranged around the toroid. The first secondary winding of the current sensor is located nearer the primary conductor than the second secondary winding of the supply transformer.

Abstract: A high-sensitivity electromagnetic relay comprises a magnetic circuit polarized by a permanent magnet, a flux distributor, an operating coil, and a moving core cooperating with the flux distributor by means of an air-gap. A return spring passes completely through the core being inserted between the flux distributor and the external end of a guide tube, which is shaped as a bottle-neck having a widened part housing the core, and a narrow part capable of sliding in an aperture.

Abstract: A ground fault trip unit of the three-pole type, comprises a fourth conductor passing through the differential transformer. The fourth conductor is connected to terminals located on a different face from that of the terminals of the other three conductors. The same ground fault trip unit can be associated with a three-pole breaking device, in which case the fourth conductor is not used, and with a four-pole device whose fourth pole is connected to the fourth conductor of the ground fault trip unit.

Abstract: The invention relates to a polarized electromagnetic relay with magnetic latching and sliding armature.The magnetic circuit comprises a tubular frame enclosed by two flanges (22, 24), a permanent magnet (14) with axial magnetization fitted between one (22) of the flanges and a flux-diverter (26), and a cylindrical trip coil (30) mounted on a bushing inside the frame (20). The other flange (24) is fitted with a tubular sleeve (46) made of ferromagnetic material coaxially surrounding a part of the moving armature (16) with a uniform radial air gap (jl) interposed. The axial overlapping distance (L) of the armature (16) by the sleeve (46) in the latched position of the relay (10) is greater than the thickness (11) of the flange (24) and/or than that of the frame (20).

Abstract: High-current, current-limiting circit interrupter having arcing contacts connected in parallel with the main contacts. Impetus means open the main contacts strikingly to switch the short-circuit current to the high-resistance arcing circuit. Electrodynamic means cause the arcing contacts to remain closed a short lapse of time after the transfer of the short-circuit current to the arcing circuit. Further electrodynamic means cause the arcing contacts to open sequentially.

Abstract: Circuit interrupter having a magnetic circuit energized by the current flowing through the interrupter and an induction plate that is movable with the movable contact of the interrupter. The abrupt rising of a fault current induces secondary currents in the induction plate which is located in the air gap of the magnetic circuit as long as the interrupter is in the closed-circuit position. The secondary currents tend to expel the induction plate from the air gap thereby moving the movable contact vigorously away from the magnetic circuit.