A centrifugal fan noise-lowering structure includes a frame having an upper and a lower cover and a sidewall, which together internally define a receiving space communicable with an air inlet and an air outlet of the frame; a stator assembly located in the receiving space and fixedly mounted on the lower cover; and a rotor assembly correspondingly assembled to the stator assembly. The receiving space is internally defined a high pressure zone and a low pressure zone. The upper cover is provided with an airflow passage, which has an inlet located at a position corresponding to the high pressure zone, and an outlet located at a position corresponding to the low pressure zone. With the airflow passage, air in the high pressure zone can be guided to jet out to the low pressure zone to thereby reduce noise produced by the centrifugal fan during its operation.

A centrifugal fan noise-lowering structure includes a frame having an upper and a lower cover and a sidewall, which together internally define a receiving space communicable with an air inlet and an air outlet of the frame; a stator assembly located in the receiving space and fixedly mounted on the lower cover; and a rotor assembly correspondingly assembled to the stator assembly. The receiving space is internally defined a high pressure zone and a low pressure zone. The upper cover is provided with an airflow passage, which has an inlet located at a position corresponding to the high pressure zone, and an outlet located at a position corresponding to the low pressure zone. With the airflow passage, air in the high pressure zone can be guided to jet out to the low pressure zone to thereby reduce noise produced by the centrifugal fan during its operation.

Provided are a vacuum pump, a magnetic bearing device, and a rotor that suppress swinging and vibration of a rotor. A vacuum pump includes, in the following order in the exhaust direction of a gas, the center of gravity of a rotor, an active radial bearing that supports the rotor in the radial direction in a non-contact manner by using a magnetic force, and a passive radial bearing that supports the rotor in the radial direction in a non-contact manner using a magnetic force.

Provided are a vacuum pump, a magnetic bearing device, and a rotor that suppress swinging and vibration of a rotor. A vacuum pump includes, in the following order in the exhaust direction of a gas, the center of gravity of a rotor, an active radial bearing that supports the rotor in the radial direction in a non-contact manner by using a magnetic force, and a passive radial bearing that supports the rotor in the radial direction in a non-contact manner using a magnetic force.

A magnetic suspension bearing device, a compressor and a method for adjusting catcher bearing gap. The magnetic suspension bearing device includes: a housing; a rotor in the housing; a magnetic bearing assembly between the housing and the rotor; a catcher bearing bracket mounted axially to an end of the housing, with a catcher bearing mounted at a radially inner side of the catcher bearing bracket; and a washer between the catcher bearing bracket and the end of the housing; wherein the washer includes a plurality of sub-washer portions, such that when the catcher bearing bracket is moved axially relative to the end of the housing to separate from the washer while still being supported by the end of the housing, the plurality of sub-washer portions can be radially removed and mounted.

A magnetic suspension bearing device, a compressor and a method for adjusting catcher bearing gap. The magnetic suspension bearing device includes: a housing; a rotor in the housing; a magnetic bearing assembly between the housing and the rotor; a catcher bearing bracket mounted axially to an end of the housing, with a catcher bearing mounted at a radially inner side of the catcher bearing bracket; and a washer between the catcher bearing bracket and the end of the housing; wherein the washer includes a plurality of sub-washer portions, such that when the catcher bearing bracket is moved axially relative to the end of the housing to separate from the washer while still being supported by the end of the housing, the plurality of sub-washer portions can be radially removed and mounted.

This disclosure relates to an axial magnetic bearing for a centrifugal refrigerant compressor, and a corresponding system and method. A centrifugal refrigerant compressor system according to an exemplary aspect of the present disclosure includes, among other things, an impeller connected to a shaft, and a magnetic bearing system supporting the shaft. The magnetic bearing system includes an axial magnetic bearing, which itself includes a first permanent magnet configured to generate a first bias flux, a second permanent magnet axially spaced-apart from the first permanent magnet and configured to generate a second bias flux, and an electromagnet. The electromagnet includes a coil arranged radially outward of the first and second permanent magnets, and the electromagnet is configured to selectively generate either a first control flux or a second control flux to apply a force to the shaft in a first axial direction or second axial direction opposite the first axial direction, respectively.

A shaft assembly for use with a turbine engine includes a shaft and a magnetic mode control unit. The shaft extends along an axis and is configured to rotate about the axis. The magnetic mode control unit is configured to control deflection of the shaft as the shaft rotates about the axis.

An electromagnet unit in which influence of a noise on a displacement sensor is suppressed and which can be installed in a space-saving manner and a vacuum pump including the electromagnet unit are provided. An electromagnet unit includes a radial electromagnet which controls a shaft to a predetermined position, a radial sensor which detects a position of the shaft, and a printed board interposed between the radial electromagnet and the radial sensor and on which a wiring pattern for sensor connecting coils of the corresponding two radial sensors to each other and a wiring pattern connecting coils of the corresponding two radial electromagnets to each other are provided. The wiring pattern for sensor and the wiring pattern for electromagnet are disposed so as not to overlap when seen from the axial direction.

Disclosed is a method for calibrating at least one gap sensor, the at least one gap sensor being provided on a magnetic bearing supporting a floating body in a non-contact manner by an electromagnetic force, the at least one gap sensor being configured to detect a gap between the floating body and a reference object that serves as a positional reference for position control of the floating body. The method includes: constructing a transformation formula for transforming an output of the at least one gap sensor into the gap using three or more constraints that are set as conditions for associating the gap with the output of the at least one gap sensor.