A magnetically levitated motor includes a stator, a rotor configured to rotate relative to the stator, and a passive radial magnetic bearing configured to support the rotor relative to the stator in a radial direction. An active longitudinal magnetic bearing is configured to selectively position the rotor relative to the stator in an axial direction.

Magnetic levitation bearing structure includes a cylinder body, a rotating shaft, a motor stator, a motor rotor, an axial bearing, a radial bearing and a displacement sensing device; the displacement sensing device, the axial bearing stator, and the radial bearing stator are directly fixed on an inner wall of the cylinder body.

A tool includes a device including a housing and a rotor, the rotor to rotate about a longitudinal axis, and an axial gap generator including a stator assembly positioned adjacent to the rotor. The axial gap generator generates a voltage signal as a function of a gap spacing between the stator assembly and the rotor, the gap spacing being parallel to the longitudinal axis.

The subject matter described herein includes a magnetic bearing assembly and an arrangement of position sensors for the magnetic bearing assembly. In one example the magnetic bearing assembly includes a rotor for fixedly coupling to a shaft for rotating with the shaft. The assembly further includes at least one stator assembly located adjacent to the rotor and circumferentially surrounding the shaft. The stator assembly includes a control coil for magnetically supporting the rotor. The stator assembly further includes a plurality of position sensors that are circumferentially spaced from each other and that extend radially from the stator assembly for measuring an indication of axial displacement of the rotor.

A position detection device of active magnetic bearings (AMB's) maintaining the position of a rotating shaft and comprising two sensing inductance coils, the position detection device comprising a programmable digital component for generating a 25 KHz square waveform signal, a current amplifier receiving the 25 KHz square waveform signal and injecting two identical control currents in the two sensing inductance coils, a differential amplifier for amplifying a voltage difference between the resulting voltages in the two sensing inductance coils and, depending on the displacement of the rotating shaft, an analog to digital (A/D) converter for delivering a position value from the voltage difference.

A rotor sensor target for magnetic bearings, the rotor sensor target comprising a ring-shaped assembly of magnetic material mounted on a generally ring-shaped assembly of non-magnetic material. The magnetic and non-magnetic ring shaped assemblies are coaxially arranged and mounted on a shaft having a longitudinal axis of rotation X′-X. The generally ring-shaped assembly of non-magnetic material comprises at least one ring-shaped slit having the longitudinal axis X′-X and may be made of a cheaper material, such as aluminum. The ring-shaped slit provides flexibility which permits operation over a wide range of temperatures without risking of damaging the ring-shaped assembly of magnetic material.

A position deviation calculated by a subtractor of a vacuum pump is input to the PIDs of three modes. The first PID is a PID controller for a high-bias mode, the second PID is a PID controller for a high-rigidity mode, and the third PID is a PID controller for a low-rigidity mode. The output signal of the third PID is extracted as a change of an indicator current for each clock of a PWM frequency and then the mean value of a change of an indicator current for several clocks is determined in a calculating unit. At this point, a switching control unit performs an operation on whether the mean value of the averaged change of the indicator current is larger than a preset redetermined value and then according to the result, an α value is outputted in the range of 0 to 1 from the switching control unit.

A bearing arrangement includes a shaft, at least one contact bearing and at least one non-contact bearing and a controller. The controller is configured to control a magnitude of a restoring force applied to the shaft by the non-contact bearing in accordance with a sensed parameter such that a stiffness of the shaft is modified such that one or more resonance frequencies of the shaft are moved away from one or more external forcing frequencies.

A discharge excitation gas laser device may include a laser chamber in which a laser gas containing a halogen gas is encapsulated, a pair of discharge electrodes disposed to face each other inside the laser chamber, a fan disposed inside the laser chamber to make the laser gas flow between the pair of discharge electrodes, a motor for rotating the fan, a motor power supply for supplying power to the motor, a magnetic bearing configured to levitate the rotary shaft of the fan magnetically, a displacement sensor for detecting the position of the rotary shaft through a can, and a controller configured to measure the rotational speed of the fan on the basis of a detection signal from the displacement sensor and control the motor power supply in such a manner that the measured rotational speed becomes a target rotational speed.

A device for estimating the sensitivity of a position sensor for a magnetic bearing supporting a rotor, the sensor being capable of measuring the position of the rotor in relation to the magnetic bearing, the magnetic bearing including at least one shaft provided with at least two radially opposite coils. The device includes a control, a current-measuring component, a component for measuring the initial position of the rotor, a component for determining a variation in currents, a component for determining a movement of the rotor, and a component for determining the sensitivity of the sensor, configured to determine the sensitivity of the position sensor based on a movement setpoint and on the value of a movement of the rotor.