Magnetic suspension device of a rotor placed in a sealed enclosure

Magnetic suspension device for a rotor placed in a sealed enclosure, comprising at least two active radial electromagnetic bearings servocoupled by means of position detectors to support the rotor without contact, each bearing comprising an annular armature of laminated magnetic material mounted on the rotor and a stator composed of electromagnetic windings associated with a yoke of laminated magnetic material which has end pole pieces positioned at a short distance from the annular armature, but without contact with the latter, and the electromagnetic windings being all positioned outside the sealed enclosure, wherein the sealed enclosure includes fluid-tight walls at least some portion of which is formed of non-magnetic material, each stator yoke of laminated material being extended to the level of the end pole pieces by a terminal portion of non-laminated magnetic material, of little thickness, constituted by a jacket formed by a metal sheet of a magnetic material of high resistivity and of permeability greater than about 200, arranged perpendicular to the lines of the magnetic field and joined by welding in fluid-tight manner to portions of the non-magnetic fluid-tight wall through sections of fluid-tight wall which have undulations capable of absorbing the differences in expansion of the sections of wall of non-magnetic material and metal, the air-gap of an electromagnetic bearing being determined by said annular armature and the surface within the enclosure of said terminal portion forming part of the fluid-tight wall.

Magnetic suspension device for a rotor placed in a sealed enclosure, comprising at least two active radial electromagnetic bearings servocoupled by means of position detectors to support the rotor without contact, each bearing comprising an annular armature of laminated magnetic material mounted on the rotor and a stator composed of electromagnetic windings associated with a yoke of laminated magnetic material which has end pole pieces positioned at a short distance from the annular armature, but without contact with the latter, and the electromagnetic windings being all positioned outside the sealed enclosure, wherein the sealed enclosure includes fluid-tight walls at least some portion of which is formed of non-magnetic material, each stator yoke of laminated material being extended to the level of the end pole pieces by a terminal portion of non-laminated magnetic material, of little thickness, which constitutes directly a portion of the wall of the sealed enclosure and is attached by welding to the portions of non-magnetic fluid-tight wall which are not situated opposite the annular armature, the air-gap of an electromagnetic bearing being determined by said annular armature and the surface within the enclosure of said terminal portion forming part of the fluid-tight wall, said position detectors being of the electromagnetic type and comprising an annular armature of laminated magnetic material mounted on the rotor and a stator composed of electromagnetic windings arranged outside the sealed enclosure and associated with a yoke of laminated magnetic material which has end pole pieces extended by a terminal portion of ferrite rod which constitutes directly a portion of the wall of the sealed enclosure and is attached by welding to the continuous wall portions of non-magnetic material.