A machine learning device learns a control condition for a magnetic bearing device that includes a magnetic bearing having a plurality of electromagnets that apply an electromagnetic force to a shaft. The machine learning device includes a learning unit, a state variable acquisition unit, an evaluation data acquisition unit, and an updating unit. The state variable acquisition unit acquires a state variable including at least one parameter correlating with a position of the shaft. The evaluation data acquisition unit acquires evaluation data including at least one parameter selected from a measured value of the position of the shaft, a target value of the position of the shaft, and a parameter correlating with a deviation from the target value. The updating unit updates a learning state of the learning unit by using the evaluation data. The learning unit learns the control condition in accordance with an output of the updating unit.

Axial magnetic bearings that include a primary winding(s) and one or more compensation windings that provide compensation such that operation of the first and/or second primary windings and the compensation windings results in a net magneto-motive force of around zero ampere turns. Current can selectively flow through one or both of the primary windings of an opposing pair of axial magnetic bearings, while current flows through the compensation windings in manner that compensates for the magneto-motive force generated by the primary winding(s). In at least situations in which the number of turns for at least one pair of compensation windings is generally equal to the number of turns of each primary winding, the net magneto-motive force generated by current flowing through a primary winding of one axial magnetic bearing and through the compensation windings of both axial magnetic bearings can generally be zero.

Provided are a vacuum pump and a method for the vacuum pump in which, when contact between a rotating body and a stator is sensed, the cause of the contact can be analyzed. Contact determination is made using a threshold for rotating body contact determination for a displacement signal and a threshold for rotating body contact determination for an acceleration signal. The amount of unbalance of a rotating body is determined using a threshold for amount-of-unbalance increase determination for the displacement signal and a threshold for amount-of-unbalance increase determination for the acceleration signal. When, in one of the displacement signal and the acceleration signal, the threshold for amount-of-unbalance increase determination or the threshold for amount-of-unbalance increase determination is exceeded within a predetermined time before determination of an estimated time point of contact, the contact is determined not to be caused by an increase in accumulation of products.

One embodiment describes a rotary machine system, which includes a stator with a first tooth, a second tooth, a third tooth, and a fourth tooth; a first electromagnet that includes a first electromagnet wire wrapped around the second tooth and the third tooth and that generates a first magnetic field to attract a drive shaft; a first integrated position sensor, which includes a first sensor wire that carries a first current wrapped around the first tooth and the second tooth; a second integrated sensor, which includes a second sensor wire that carries a second current wrapped around the third tooth and the fourth tooth; and a controller that determines current position of the drive shaft based at least on change of inductance of the first sensor wire and the second sensor wire, and that instructs the first electromagnet to adjust magnitude of the first magnetic field based at least in part on the current position.

There is provided an inductive sensing circuit, comprising a signal generator, configured to generate a drive signal; one or more sensing arrangements, each of the one or more sensing arrangements comprising: two sets of one or more inductive sensing elements, configured in a half bridge arrangement, the two sets of one or more inductive sensing elements driven by the drive signal; a correction signal circuit, configured to generate a correction signal, wherein the correction signal is an adjustably scaled version of the drive signal; and a summing circuit, configured to sum an output signal of the two sets of one or more inductive sensing elements with the correction signal; and a demodulation circuit, configured to demodulate an output of the summing circuit of each of the one or more sensing arrangements.

A pump includes: a rotor; a magnetic bearing supporting the rotor by a magnetic force; a drive mechanism rotationally driving the rotor; a pump mechanism including an impeller attached to the rotor; and a control unit controlling the magnetic bearing which includes: a bearing rotor member in the rotor formed from a magnetic material; and a bearing stator member facing the bearing rotor member, the bearing stator member has: a core formed from a magnetic material; and a coil wound around the core, the drive mechanism includes: a driven member adjacent in a radial direction to the bearing rotor member; and a drive portion facing the driven member in the radial direction, and magnetically coupled to the driven member to drive the rotor, and the control unit corrects rotational position of the rotor based on a detection signal from a first sensor portion capable of detecting displacement of the rotor.

A magnetic bearing assembly is for levitating a generally drum-shaped, vertical rotor such that the drum itself is the target of magnetic actuators. The magnetic bearing assembly basically includes at least one active radial actuator configured to center the drum-shaped rotor in an annular air gap so as to enable contactless rotation. The one or more radial actuators are configured to act principally against gravity and is/are located in essentially the same vertical plane as a center of gravity of the drum-shaped rotor.

An active magnetic bearing apparatus for supporting a rotor of a rotary machine comprises an axial magnetic bearing unit and a radial magnetic bearing unit mounted directly to one another. One of the axial magnetic bearing unit and the radial magnetic bearing unit is mounted to a support for attachment to a housing of the rotary machine.

A rotation mechanism (20) of a vacuum pump (100) includes a magnetic bearing unit (21) having a first outer diameter (91), the magnetic bearing unit (21) being operable as a first radial magnetic bearing (40), and a motor unit (22) provided on a side of a second end (11b) of a rotary shaft (11) relative to the magnetic bearing unit, the motor unit (22) having a second outer diameter (92) larger than the first outer diameter, the motor unit (22) being operable as both a motor (30) and a second radial magnetic bearing (50).

A control apparatus includes a constant storage portion that stores constant values of an electromagnet coil including a resistance value Rm, an inductance Lm, a sampling time Ts, etc. A current storage portion stores previous current command values Ir having been regularly sampled by a microcomputer inside a current control circuit. A low-frequency feedback circuit generates a signal for suppressing an error between DC components and low-frequency components of an input current command value Ir and a detected current value IL and outputs the signal. An output voltage computing circuit calculates, based on the input current command value Ir[n+1], a stored value Ir[n] of the current storage portion, a stored value of a constant storage portion, and the signal of the low-frequency feedback circuit, a voltage for suppling the electromagnet coil with a current in accordance with a command, and outputs the calculated voltage.