Abstract: A trip device comprising a differential current detection transformer, a trip relay of a breaking mechanism of the circuit breaker and a test circuit for checking the operation of the trip device. The relay comprises a fixed yoke bearing a coil and a blade that is mobile with respect to the yoke. During normal operation of the trip device, the blade is held magnetically in the position pressing against the yoke and when a differential current occurs, the blade actuates the breaking mechanism. The test circuit generates a vibration of the blade, without causing tripping of the mechanism, in order to check its ability to disengage from the fixed yoke. Advantageously, this vibration is obtained by application of a voltage in the form of pulses to the terminals of the coil.

Abstract: A differential protection device includes a current transformer comprising a toroid formed by a magnetic core, primary windings formed by the active conductors of the installation and a secondary winding at the terminals of which a differential fault signal is established when a differential fault occurs in the primary windings, a tripping relay of a current breaking apparatus, and a secondary connection circuit connecting the relay to the terminals of the secondary winding, the secondary connection circuit being arranged to bring about tripping when the signal exceeds a preset threshold. The above-mentioned secondary circuit comprises a full-wave rectifier and a capacitor, connected in parallel with the secondary winding of the toroid, and the magnetic core is made of a nanocrystalline material.

Abstract: The electronics of a residual differential device is powered by several sources derived from the electrical system (14, 16, 18). A supply anomaly detector (36) signals the failure of one of the supply sources caused, for example, by a break in one of the wires (14, 16, 18). The anomaly detector signals the break in this wire and sends a tripping order to the protection circuit breaker (10). Voltage in the phase conductors is monitored, and an alarm device is energized, for example, if one of the phase conductors is open.

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).