Centre National De La Recherche Scientifique

Electricite De France

Institut Polytechnique De Grenoble

Dcns

Etat Francais Represente Par Le Delegue General Pour L'armement

Institut National Polytechnique De Grenoble

Olivier Nicolas Chadebec

Jean-Louis Coulomb

Laure-Line Rouve

Yannick Vuillermet

Laurent Demilier

Gilles Cauffet

Didier Cavallera

Bruno Caillault

Francois-Xavier Zgainski

A method of taking a plurality of measurements of the magnetic field using the plurality of sensors; includes assessing the inductive magnetic excitation; and determining the likely distribution of magnetic sources on the surface of the hull by resolving a system of equations derived from modeling the physical phenomena at play, on the basis of the plurality of measurements taken and the assessed inductive magnetic excitation. The model describes the induced magnetic sources as a distribution of dipolar sources and the remanent magnetic sources as a distribution of monopolar sources. A device () for determining the magnetization of the hull of a ship for implementing the method is also described.

Method for determining the magnetisation of the hull of a ship, and associated device

A method and a system for controlling the switching time of a device that includes a magnetic circuit and a conductive winding. The method includes acquiring a measurement of the magnetic field generated by the residual flux, by a sensor placed near the magnetic circuit; processing the acquired measurements to infer the residual flux in the magnetic circuit; determining, on the basis of the residual flux, the optimal time for switching on the device. The method also includes switching on a three-phase transformer. The transformer includes a primary conductive winding and a secondary conductive winding surrounded by an enclosure. A magnetic field sensor is on the magnetic circuit and/or on one outer surface of the enclosure.

Method and system for controlling the turn-on time of a device that includes a magnetic circuit

The invention concerns the field of devices and appliances for measuring the intensity and the direction of the magnetic field emitted by a plate or a structure, such as for example a ship's hull and it particularly concerns a method for determining the magnetisation and the magnetic field radiated by a ferromagnetic plate using magnetic field sensors distributed along said plate and at known positions relative thereto. The invention is characterised in that it consists in: producing a mesh of said plate by clipping into elementary surfaces; producing a first modelling of the magnetic field associated with measurements and based on the produced surface meshing of the plate, on its thickness, on measurements, on co-ordinates of measurement points and on the excitation B=&#x3bc;H; producing a second modelling of the physical behaviour of the material forming the plate based on the mesh, its thickness, the excitation, and the reversible permeability of the material; calculating the permanent and induced magnetisation levels of each of the elementary surfaces based on said first and second modelling and on the measurements performed by said magnetic field sensors; calculating the magnetic signature of the plate in every point based on said permanent and induced magnetisation levels of each of the elementary surfaces, the surface mesh produced on the plate, its thickness, measurements, co-ordinates of the calculation points and the excitation B=&#x3bc;H.

Method for determining magnetization and the field radiated by a ferromagnetic plate

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Grenoble, France

Olivier Nicolas Chadebec