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.

A thrust magnetic bearing includes a stator having a coil, and a rotor. The stator includes main and auxiliary stator magnetic-pole surfaces. The rotor includes main and auxiliary rotor magnetic-pole surfaces facing the main and auxiliary stator magnetic-pole surfaces. When an electric current flows in the coil, an electromagnetic force in an axial direction is generated between the main stator and rotor magnetic-pole surfaces, and an electromagnetic force in a radial direction is generated between the auxiliary stator and rotor magnetic-pole surfaces. When the rotor is displaced in the radial direction, a radial force that acts on the rotor between the auxiliary stator and rotor magnetic-pole surfaces is increased in a direction of the displacement, and a radial force that acts on the rotor between the main stator and rotor magnetic-pole surfaces is increased in a direction opposite to the direction of the displacement.

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).

Provided is a magnetic levitation power system. The magnetic levitation power system includes: a magnetic power system disposed on a wheel hub and a driver shaft, where the magnetic power system generates a power capable of enabling a movement of the wheel hub through an interaction of magnetic fields between the wheel hub and the driver shaft; a first magnetic levitation system disposed on the wheel hub and the driver shaft, where the first magnetic levitation system is capable of enabling the wheel hub and the driver shaft to be in a levitation state within a circumferential extent of 360 degrees with the wheel hub being opposite to the driver shaft through the interaction of the magnetic fields between the wheel hub and the driver shaft; and a second magnetic levitation system disposed on the wheel hub and the driver shaft, where the second magnetic levitation system is capable of enabling the wheel hub and the driver shaft to be in a levitation state in a direction of a central axis of the wheel hub through the interaction of the magnetic fields between the wheel hub and the driver shaft. The present invention solves the problems of high hardware costs, low energy utilization rate, environmentally harmful characteristics, etc. of the existing automobile power system.

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.

A magnetic bearing device comprises a stator (30) and a rotor (10) supported in the stator for rotation around a rotation axis (R). The rotor comprises at least one permanent magnet (21, 22) that is magnetized along the rotation axis. The stator comprises at least one closed magnetic core (31) that surrounds the rotor (10) and at least one radial bearing winding (32) arranged on the closed magnetic core (31) in a toroidal configuration. The at least one radial bearing winding is arranged to interact with a permanent magnetic field generated by the at least one permanent magnet to obtain a radial bearing force when current is supplied to the at least one radial bearing winding.

A turbo chiller that has an oil-free configuration, which reduces the frequency of maintenance and maintenance-induced release of refrigerant, and can achieve a reduced environmental impact by utilizing the characteristics of the low-pressure refrigerant R1233zd(E) that reaches negative pressure at a saturation temperature of 18° C. or lower. The turbo chiller comprises a refrigeration cycle that includes a turbo compressor, a condenser, a decompression device, and an evaporator connected in sequence via piping and is filled with a refrigerant; wherein the refrigerant is a low-pressure refrigerant R1233zd(E) refrigerant with low global warming potential and low ozone depletion potential; the turbo compressor has a direct drive configuration in which a rotating shaft of impellers is directly joined to a motor; and the rotating shaft is supported by magnetic bearings.

A downhole-type system includes a rotatable shaft; a sensor that can sense an axial position of the shaft and generate a first signal corresponding to the axial position of the shaft; a controller coupled to the sensor, in which the controller can receive the first signal generated by the sensor, determine an amount of axial force to apply to the shaft to maintain a target axial position of the shaft, and transmit a second signal corresponding to the determined amount of axial force; and multiple magnetic thrust bearings coupled to the shaft and the controller, in which each magnetic thrust bearing can receive the second signal from the controller and modify a load, corresponding to the second signal, on the shaft to maintain the target axial position of the shaft.

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 gas laser apparatus includes: a magnetic bearing including an electromagnet capable of controlling a magnetic force, and configured to rotatably support a rotary shaft of a fan in a magnetically levitated state by the magnetic force, the fan being configured to supply a laser gas; an electromagnet control unit configured to control the magnetic force of the electromagnet based on displacement of a levitated position of the rotary shaft and adjust the levitated position; a motor configured to generate torque for rotating the fan; a magnetic coupling configured to couple the rotary shaft and a drive shaft of a motor with a magnetic attractive force and transmit the torque of the motor to the rotary shaft; an attractive force estimating sensor configured to detect a parameter that enables an attractive force of the magnetic coupling to be estimated; an attractive force measuring unit configured to measure the attractive force of the magnetic coupling based on the detected parameter; and a correction unit configured to correct the magnetic force of the electromagnet according to a variation in the attractive force measured by the attractive force measuring unit.