Abstract: An electric motor comprises a stator element made of magnetic material, a moving element made of magnetic material and carrying at least one permanent magnet and adapted to run along sections of the stator element while defining two constant air-gaps by means of which the magnetic flux of the permanent magnet closes up in said stator element, and at least one coil wound around at least one of said sections. At least a pair of stops delimits a given clearance for the moving element along the coil. The movable element bears against either of the stops as a function of the direction of the direct current applied to the coil and remains magnetically locked thereto by means of a magnetic portion of the stops through which passes part of the magnet flux.

Abstract: The deformations of an object subjected to stresses are measured, said object being, for example, an inertia wheel revolving at high speed inside a vacuum chamber, light pulses emitted by a stroboscope and synchronized with the rotation speed of the object are directed onto this object. The still frames or freezes thus formed are issued from the chamber through a circular aperture via a first large focal length objective. On the full scale real images thus obtained within a plane, a reticule is superimposed and the images of the object and of the reticule are increased by means of a second objective. A video camera connected to a screen and a recorder makes it possible to directly display and/or store the images of the deformations sustained by the object.

Abstract: A polyphase electric motor including a body mobile relative to a fixed body, one of these bodies carrying an exciter strip formed by a plurality of alternating coil windings aligned with each other and connected to an energizer device including a switch adapted to excite the pluralities of coils alternately, the other body comprising a row of alternating magnets and, one on each side of this row, two magnetic bars determining along the row an airgap of constant width in which the exciter strip is disposed. The permanently magnetized row is disposed parallel to the magnetization directions of the magnets constituting it between two continuous magnetic plates.

Abstract: A magnetic bearing secures active magnetic centering with respect to at least one centering axis of a body movable relative to another a static body. It comprises, on each side of a plane of symmetry perpendicular to the centering axis and containing a reference axis: at least one permanent magnet magnetized parallel to the reference axis, at least one combination comprising a coil wound on a ferromagnetic core disposed to procure a magnetic flux parallel to the reference axis and ferromagnetic members adapted to provide a closed magnetic path for magnetic flux produced by the magnet and the coil via airgaps on the centering axis separating the movable body from the body body. A control circuit comprises a sensor responsive to relative movement between the movable body and the body body along the centering axis and adapted to feed to the coil a current adapted to correct any such relative movement. Two ferromagnetic plates carried by the body body have the magnet and the core clamped between them.

Abstract: A device for temporarily locking onto a stator a rotor that normally rotates on the stator on magnetic bearings (such as an inertia wheel in a space satellite) includes a frustoconical bearing surface near the periphery of the rotor and a complementary frustoconical bearing surface on the stator. The rotor bearing surface is axially engaged with the stator bearing surface by a cable forming an annular loop in a transverse plane. A device is provided for releasing this cable. A plurality of radially mobile elementary bearing surfaces are coupled to the stator and there is a second bearing surface at the periphery of the rotor. These elementary bearing surfaces are axially engaged with the second bearing surface on the rotor, against the action of a return spring arrangement, in the direction opposite that in which the conical bearing surface on the stator applies an axial engagement force to the frustoconical bearing surface on the rotor.