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: The tripping adjustment range of a magnetic trip device with a plunger core is increased by providing, in the movable plunger core, a groove whose edges define polar surfaces bounding air-gaps with the edges of the yoke in such a way as to generate in the minimum adjustment position a force which is added to the attractive force of the movable core by the stationary core, and inversely a force in the maximum adjustment position which is subtracted from the attractive force of movable plunger core. The trip device excitation coil is offset with respect to the yoke to increase the adjustment range, and a return device with adjustable stop and decreasing return force as the movable core approaches the stationary core, contributes to increasing this tripping threshold adjustment range.