Skf Magnetic Mechatronics

Societe De Mecanique Magnetique

Skf Canada Limited

Ulrich Schroeder

Maurice L Brunet

Eduardo Carrasco

Yann Tremaudant

Joaquim Da Silva

Luc Baudelocque

Frederic Ponson

Lateb Ramdane

Yves Dupuis

Erwan Salahun

Olivier Lemarchand

Udell So

Frédéric Ponson

Matthew Nesbitt

Eric Helene

Bertrand Haffray

Ramdane Lateb

Bertrand Barbey

A balancing method for balancing at high speed a flexible rotor of a rotary machine, the rotary machine having a stator, and the rotor being supported in the stator by at least two radial magnetic bearings. The balancing method including a step of placing the rotor inside the stator, a step of performing at least one first run in order to identify amplitude and angular location of the unbalance in a first speed range below critical speed, a step of placing first balancing masses inside the rotor on predefined first balancing planes, a step of performing at least one second run in order to identify amplitude and angular location of the unbalance in a second speed range above critical speed, and a step of placing second balancing masses inside the rotor on predefined second balancing planes.

Balancing method for balancing at high speed a rotor of a rotary machine

A rotary machine provides a stator having a stator casing, and a rotor shaft having a rotational axis and supported in the stator casing by at least one radial magnetic bearing. The rotary machine further provides an axial mechanical thrust bearing being disposed proximate a radial surface of one end of the rotor shaft, the axial mechanical thrust bearing, including a rolling element located on the rotational axis of the rotor shaft.

Rotary machine having magnetic and mechanical bearings

A device for detecting the axial position of a rotor shaft of a rotary machine having a stator and a rotor is provided. The detecting device includes a sensor stator ring, secured to the stator, made from ferromagnetic material, facing the shoulder of one end of the hollow or not hollow rotor shaft and arranged so as to leave an axial airgap with the one end of the rotor shaft. The sensor stator ring having at least one annular slot receiving an annular induction coil. The rotor shaft is made from solid magnetic steel, an outer end of the rotor shaft acts as a target surface whose axial position is to be measured by the sensor stator ring.

Device for detecting the axial position of a rotor shaft and its application to a rotary machine

A hybrid magnetic suspension of a rotor () having compressor wheels () having permanent magnets () integral to shrunk fit rings () arranged on the rotor () in the vicinity of the compressor wheels (), permanent magnets () integral to stationary rings () coaxially arranged with the rotor () and associated with a resilient material () to define a passive radial magnetic bearing, coils () associated with magnetic armatures () and facing rotor parts () being located perpendicularly to the rotor (), and axial sensors () configured for sensing the axial position of the rotor () and control means () configured for feeding the coils () as a function of the outputs of the axial sensors () for generating both axial bearing forces and a motor torque and thereby being adapted for defining an axial bearingless motor.

Hybrid magnetic suspension of a rotor

A permanent magnet rotor assembly includes a cylindrically shaped shaft having an outer surface, a plurality of permanent magnets constituting portions of annular segments and an outer retaining cylindrical sleeve surrounding the plurality of permanent magnets. The assembly further includes a cylindrical magnet housing mounted on the cylindrically shaped shaft for supporting the plurality of permanent magnets. The cylindrical magnet housing is formed of a magnetic material. The retaining cylindrical sleeve is preloaded by a resultant interference fit IF2 defined by the following formula IF2=&#x2212;&#xd8;Y+&#x221a;{square root over (((&#xd8;Y+IF1)^2+&#xd8;Y^2&#x2212;&#xd8;X^2))}, where &#x3a6;Y is an external diameter of the plurality of permanent magnets, &#x3a6;X is an internal diameter of the cylindrical magnet housing, and IF1 is a primary interference fit between an external diameter of the cylindrically shaped shaft and the internal diameter of the cylindrical magnet housing.

Rotor assembly with permanent magnets and method of manufacture

A high speed energy storage flywheel comprises a rotor which is located in a vacuum chamber provided in a stator housing and is supported by magnetic bearings with respect to the stator housing. A fluid tank used for releasing in a controlled manner, a fluid inside the vacuum chamber and therefore create a braking effect on the rotor by friction.

High speed flywheel on magnetic bearings

A device for detecting the axial position of a rotary shaft of a rotary machine comprises a target of ferromagnetic material placed at the end of the rotary shaft, an induction coil associated with a stationary magnetic circuit and placed facing the target while leaving an airgap, and a power supply circuit. The power supply circuit comprises an AC voltage source connected between a first end of the induction coil and a zone situated at a reference voltage, at least one capacitor connected between the ends of the induction coil, and a detector device interposed between a second end of the induction coil and the zone situated at the reference voltage, in order to deliver on a line information about the magnitude of the current flowing between the second end and the zone situated at the reference voltage.

Device for detecting the axial position of a rotary shaft and its application to a turbo-molecular pump

An active magnetic bearing () with autodetection of position, the bearing comprising at least first and second opposing electromagnets () forming stators disposed on either side of a ferromagnetic body () forming a rotor and held without contact between said electromagnets. The first and second electromagnets () each comprising a magnetic circuit () essentially constituted by a first ferromagnetic material and co-operating with said ferromagnetic body to define an airgap, together with an excitation coil () powered from a power amplifier whose input current is servo-controlled as a function of the position of the ferromagnetic body relative to the magnetic circuits of the first and second electromagnets. The position of the ferromagnetic body () being measured from the inductance detected between the two electromagnets () in response to simultaneous injection into both opposing electromagnets of a sinusoidal current at a frequency that is greater than the closed loop passband of the system. The magnetic circuit () of each electromagnet further includes a portion () in the vicinity of the excitation coil () that uses a second ferromagnetic material having magnetic permeability that is lower than that of the first material and electrical resistivity that is higher than that of the first material so as to encourage the passage of the high frequency magnetic fields that are generated in the bearing.

Active magnetic bearing with automatic detection of the position thereof

The present invention provides a circuit for monitoring harmonic distortion in the power supply of a synchronous electrical machine with permanent magnet excitation that comprises a rotor without a damper cage, a stator with first, second, and third windings, a frequency converter, and control circuits for controlling the frequency converter. The monitoring circuit comprises means for obtaining at least one signal representative of the current in the first winding of the stator and at least one signal representative of the current in the second winding of the stator; a circuit for generating synchronizing pulses reflecting the electrical frequency fn of rotation of the rotor relative to the stator; means for determining a signal representative of the current in the third winding of the stator; a set of band-stop notch filters respectively receiving said signals representative of the currents in the first, second, and third windings, and each presenting a center frequency that is servo-controlled to the electrical frequency fn of rotation of the rotor, in order to reject the harmonic corresponding to said electrical frequency fn; a set of measurement circuits for measuring the harmonics that remain in the signals output by each of the band-stop notch filters; and a comparator circuit for continuously comparing the greatest of the values of the signals from the measurement circuits relative to an alarm threshold.

Circuit for monitoring harmonic distortion in the power supply of a synchronous electrical machine with permanent magnet excitation

The rotary machine comprises a rotary shaft () supported by first and second radial magnetic bearings () that are electrically controlled by a control device (), said rotary shaft being fitted with an axial abutment device () comprising a rotor formed by a disk () secured to the rotary shaft () and interposed between first and second stators () formed annularly around the rotary shaft and each including at least one annular coil () controlled electrically by a system for servo-controlling the axial position of the rotary shaft. The stator () of the axial abutment device () further comprises a secondary induction circuit (), and the disk () secured to the rotary shaft comprises a primary induction circuit () so that during rotation of the shaft, electricity is excited in the secondary induction circuit in order to supply energy to the radial magnetic bearings.

Rotary machine with axial stop incorporating a current generator

The active magnetic bearing () comprises a stator () fitted with electromagnet windings () and a first stack of ferromagnetic laminations (), a rotor () fitted with a second stack of ferromagnetic laminations (), servo-control circuits (), and position detectors (). The first stack of ferromagnetic laminations () comprises in succession in the axial direction: at least a first sub-set () of laminations () presenting first notches housing electromagnet windings (); a second sub-set () of laminations () presenting both first notches housing electromagnet windings () and second notches housing a radial detector (); and a third sub-set () of laminations () presenting first notches housing electromagnet windings (). The first stack of ferromagnetic laminations () further comprises fourth and fifth sub-sets () of laminations () at its ends, presenting the same notches as each other and housing respective first and second axial detectors ().

Active magnetic bearing with integrated detectors

A device for detecting angular position for controlling a synchronous motor with permanent magnet excitation. The detector device comprises a calculation circuit (,) having measurement means (,) for measuring the voltage V,of a given phase U, first subtracter means (,) for subtracting from the voltage V,as determined by the measurement means (,) a magnitude (C,) corresponding to the resistive voltage drop across the resistance (R,) of the winding under consideration carrying a current i,, integrator means (,) for integrating the signal from the first subtracter means (,), second subtracter means (,) for subtracting from the signal delivered by the integrator means (,) a magnitude (C,) corresponding to the inductive voltage drop across the inductance (L,) of the winding under consideration carrying the current i,, and a comparator circuit (,) for detecting the zero crossings of the rotor flux sinewave signal as delivered by the second subtracter means (,) and thus for supplying an information signal identifying the angular position of the rotor relative to the stator. The angular position detector device avoids any need to make use of sensors of the Hall effect type or of the inductive type.

Growing community of inventors

Mont Saint Aignan, France

Ulrich Schroeder