Societe Europeenne De Propulsion

Societe De Mecanique Magnetique S.a.

Societe Europeene De Propulsion

Leybold-Heraeus Gmbh & Co. Kg

Societe De Mecanique Magnetique

Societe Anonyme Dite: Societe Europeenne Depropulsion

Societe Anonyme Styled: Societe Europeenne De Propulsion

Societe De Propulsion-s.e.p.

Societe Anonyme Dite: Societe Europeene De Propulsion

Societe Anonyme: Societe De Mecanique Magnetique

Helmut Habermann

Maurice L Brunet

Jean Jolivet

Pierre Joly

Werner Bachler

Rudiger Frank

Alain Gerbier

Jacques LeClere

Pierre Lemerle

Andre Tassel

A vibrator acting in a low frequency vibration domain, for fixing to and applying low frequency vibrations on a frame in a first predetermined direction along an axis X'X. The vibrator comprises: a first structure having cylindrical pole pieces cylindrical about an axis coaxial to said predetermined direction X'X and provided at their peripheries with coils, and at least one means for creating a magnetic field for causing a magnetic flux to be established between the cylindrical pole pieces; a second structure comprising a cylindrical ferromagnetic mass coaxial about the axis X'X and having cylindrical pole pieces whose peripheries are situated facing respective ones of the coils, and enabling magnetic flux to be established through the ferromagnetic mass; radial active magnetic bearings for holding the second structure radially relative to the first structure without making contact therewith; at least one detector for detecting vibrations along the axis X'X; and circuits for servo-controlling the current flowing in the coils as a function of signals delivered at least by the detector.

Large-amplitude low-frequency vibrator

The auxiliary bearing comprises a chromium steel rotor (2) mounted on the rotary shaft (1), a graphite stator (3) mounted on the frame (5) and disposed to face the rotor (2) and to leave clearance relative thereto which is narrower than the air gap in the magnetic bearings which constitute the main supports of the rotary shaft, a network (4) of liquid feed channels opening out into the empty space between the rotor (2) and the stator (3), and selective control means for controlling the supply of liquid through said network of feed channels. The auxiliary bearing may be of the radial clearance type or of the axial clearance type.

Auxiliary bearing having a graphite stator for a rotary shaft mounted on

A combination vibration generator and dampener having magnetic suspension and servo-control along three axes includes a hollow outer body fixed to a structure whose vibration is to be controlled, and an inner body which is essentially spherical in shape and which is inside the hollow outer body. Six active magnetic bearing elements are diametrically disposed in pairs along three orthogonal axes and serve to hold the inner spherical body inside the hollow outer body without direct contact between the inner and outer body. At least three position detectors detect the position of the inner body relative to the hollow outer body while at least one vibration detector device detects vibration forces on the structure whose vibration is to be controlled. Control apparatus, coupled to the position detectors and the vibration detector device, receives information from the position detectors and the vibration detector device for controlling the supply of power to the six active magnetic bearing elements in order to control the movement of the inner body in such a manner as to either set up forces on the outer body tending to generate vibration in the structure, or alternatively, to cancel vibration forces detected on the structure.

Vibrator/dampener having magnetic suspension and servo-control along

Active radial magnetic bearing with solid rotor comprising a stator composed of an armature and electromagnetic coils, a rotor fast with a rotary shaft and placed opposite the stator, detectors for detecting the radial position of the rotor with respect to the stator, and servo-control circuits for adjusting the current going through the electromagnetic coils according to the value of the signals delivered by said position detectors. The electromagnetic coils are so designed as to create a rotating sinusoidal magnetic field with radial flux, the electromagnetic coils comprising a plurality of windings distributed over the periphery of the stator and supplied in succession one after another from the servo-control circuits. This type of bearing helps going through critical frequencies.

Active radial magnetic bearing with solid rotor for damping critical

The hybrid fluid bearing comprises a fixed body, a tubular part made of a nonmetallic material, mounted inside the body and having an internal bore which defines a cylindrical bearing surface, leaving a small amount of clearance relative to the shaft, which is provided with an annular magnetic circuit constituted by rectified laminations. A fixed magnetic circuit made of laminations defines a series of poles and notches disposed concentrically around the outside of the tubular part, with electromagnetic windings being disposed in the notches around the poles and being fed with electricity from servocontrol loops which receive signals from at least one vibration detector disposed on the fixed body. The cylindrical bearing surface has a series of recesses formed therein, said recesses being distributed around the circumference of the tubular part and being connected to means for feeding them with fluid and for removing fluid therefrom. Sealing means are also provided. This hybrid fluid bearing has the capacity of being heavily loaded while simultaneously highly attenuating vibrations reaching the fixed body thereof.

Hybrid fluid bearing with stiffness modified by electromagnetic effect

The electromagnetic device comprises at least one compensation ring placed in the vicinity of the fluid bearing and mounted relative to the rotor by means of an active radial magnetic bearing whose electromagnet windings are powered as a function firstly of the signals delivered by a position detector for detecting the position of the compensation ring relative to the rotor, and secondly of the signals delivered by at least two vibration detectors disposed on the casing of the machine and having nonparallel sensitivity axes which are perpendicular to the axis of the rotor. The signals delivered by the vibration detectors are applied to a high-gain narrow-band selective feedback circuit whose central frequency is synchronized with a reference frequency fo. The compensation ring is of relatively small mass and serves to exert a rotary compensation force on the rotor via the radial magnetic bearing, which force is equal to the centrifugal force due to the out-of-balance mass of the rotor but which is 180.degree. out of phase relative thereto, thereby reducing casing vibration while expending little energy.

Electromagnetic device for reducing vibration in a rotary machine fitted

This invention relates to a device for measuring the induction in the air gap of a magnetic bearing, which comprises an assembly of small notches of small width made in the longitudinal direction of the rotor and distributed on the periphery thereof, an assembly of small coils disposed in the end faces of the poles of the stator frame located opposite the rotor, parallel to said small notches, and means for detecting the alternating voltage induced in each small coil due to the passage of the small notches of the rotor opposite said small coils.

Device for measuring the induction in the air gap of a magnetic bearing

The rotor of the radial bearing comprises a central shaft and a stack of ferromagnetic laminations constituted by a set of very thin individual laminations each of which extends over a limited angular sector around the periphery of the central shaft, said laminations being disposed in parallel planes so as to constitute a succession of flat split rings extending perpendicularly to the rotor axis. The individual laminations in any given plane are angularly offset relative to the individual laminations of the adjacent planes in such a manner as to provide a stack of laminations which is staggered. A bearing in accordance with the invention is suitable for supporting large diameter shafts which rotate at high speeds.

Large diameter radial magnetic bearing

A device for reducing the vibrations of a rotating machine equipped with an active magnetic suspension comprises at least two vibration detectors located on the machine frame for detecting disturbances applied to the frame, and at least an additional selection feedback loop with narrow band and high gain whose central frequency is synchronized with a reference frequency and which receives signals delivered by the vibration detectors. The additional selective feedback loop comprises means for integrating the signals delivered by the vibration detectors and filtering means for eliminating the transient signals whose frequency is not linked to the reference frequency.

Method and device for reducing the vibrations of rotating machines

The device for measuring the longitudinal tension in a strip leaving a rolling mill or stand comprises a measuring roll over which the strip bearingly runs, said roll consisting of at least one roll mounted on active radial magnetic bearings acting as load sensors and supplying a signal based upon the tensile stress in the strip bearing on said measuring roll, and means for measuring the current flowing in the windings of the magnetic bearings, as well as means for detecting the radial position of the rolls supported by said bearings and means for measuring the air gap of the magnetic bearings and keeping said air gap substantially constant.

Device for measuring the longitudinal tension in a strip of material

The present invention relates to an active electromagnetic bearing comprising first and second sets of electromagnet coils, the two sets of coils being so placed on one armature that on each double-pole part of armature are wound one coil of the first set and one coil of the second set and that the successive coils of the first set are all wound in the same direction whereas the coils of the second set which duplicate the coils of the first set are alternately wound in the same direction and in opposite directions with respect to the corresponding coils of the first set, a detector for sensing the position of the movable member and a control circuit being associated with each set of coils, and switch-over means being provided for connecting either set of coils with the corresponding control circuit in response to a control signal.

Redundant active electromagnetic bearing

An axial electromagnetic bearing for smooth shafts of large diameter and relatively shorter length of the type comprising a stator of substantially annular shape and an armature in the shape of a disc attached to the shaft and located facing the stator, at least one axial position detector for the shaft being associated with the axial bearing, and the bearing being characterized in that the stator of the axial bearing is composed of four independent sectors each of which comprises a ferromagnetic core and a winding and each of the independent sectors of the stator of the axial bearing being controlled by at least one corresponding detector determining the axial position of the shaft in relation to the said sector.

Axial electromagnetic bearing for smooth shafts of large diameter

The invention relates to a device for compensating the gain of a circuit servo-controlling the position of a rotor with the aid of at least one electromagnetic bearing provided with electromagnet windings, from signals delivered by at least one detector detecting the position of the rotor, the servo-control circuit ensuring the control of the supply of the windings in response to the signals delivered by the detectors and comprising an amplification circuit with which is associated a negative current feedback loop, said device further comprising supplementary electrical means for injecting at the input of the amplification circuit a signal depending on the variations in the airgap of the servo-controlled electromagnetic bearing, in a predetermined variation frequency zone. The invention is more particularly applicable to electronic circuits for controlling active electromagnetic bearings.

Device for compensating the gain of a servo-controlled circuit by

The invention relates to a device for the horizontal stabilization of a mass supported vertically with the aid of springs, intended for damping the oscillations of the mass in a horizontal plane, for a given vibration frequency band, said device comprising two active electromagnetic radial bearings and at least two accelerometers placed on the mass to be stabilized. The bearings are controlled from signals furnished by the accelerometers which are sensitive to oscillations of the table in two orthogonal horizontal directions.

Device for the horizontal stabilization of a vertically supported mass

An axial electromagnetic bearing for supporting the end of a shaft rotating a high speed of the type comprising an armature in the form of a disc attached to the shaft and a fixed annular armature disposed facing the disc armature a short distance from the former so as to define a small axial air gap therebetween, the said fixed armature comprising excitation windings and a ferromagnetic core, the bearing being characterized in that radial grooves are provided in the peripheral portion of the disc and situated facing the annular fixed armature. The arrangement causes a reduction in the effect of Eddy currents without detracting from the mechanicl strength of the bearing.

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Vernon, France

Helmut Habermann