An HVAC system includes an unloading device, a centrifugal compressor, a gas foil bearing, a VFD and a controller. The controller is programmed to start the centrifugal compressor from a stopped condition by operating the unloading device to remove a load from the centrifugal compressor, accelerating the motor to a first speed above a liftoff speed of the gas foil bearing and below an operating speed of the centrifugal compressor, running the motor for a period of time, operating the unloading device to apply the load to the centrifugal compressor, and accelerating the motor to the operating speed.

A motor includes a rotor including a rotor core fixed to a rotary shaft of a compressor, and permanent magnets fixed to the rotor core, and a stator including a stator core surrounding the rotor core from outside in a radial direction about a central axis of the rotary shaft. The rotor core has a first core and a second core in a direction of the central axis. The first core has a hole portion at a center thereof in the radial direction, and has magnet insertion holes located on an outer side of the hole portion in the radial direction. The permanent magnet is inserted in the magnet insertion hole. The permanent magnet constitutes a magnet magnetic pole, and a part of the first core constitutes a pseudo magnetic pole. The second core has a shaft hole at a center thereof in the radial direction. The rotary shaft is fixed to the shaft hole. An inner circumference of the hole portion of the first core is distanced from the rotary shaft in the radial direction. The second core is located on an outer side of the stator core in the direction of the central axis.

A motor includes a stator having a core and a plurality of radially inwardly extending teeth defining slots therebetween. Each tooth has a tip having a pair of circumferentially protruding tooth projections. A first insulation sheet is inserted between each pair of the teeth and has a body part and a pair of first end parts formed by folding both ends of the body part toward each other. A second insulation sheets is arranged between the winding parts of adjacent teeth and has a body part and a pair of second end parts formed by folding both ends of the body part away from each other. The tooth projections, the second end parts and the first end parts are arranged in this order from radially inside to outside and overlap radially.

A refrigeration system that induces lubricant-liquid refrigerant mixture flow from a flooded or falling film evaporator by means of the lubricant-liquid refrigerant mixture flow adsorbing heat from an electronic component.

Disclosed is a home appliance including a claw pole type motor, the claw pole type motor include a first core including a first core main body disposed on a rotary shaft, a first elongation portion disposed in the center portion of the first core main body and extending in the axial line direction of the rotary shaft, and a plurality of first claw poles disposed in the edge portion of the first core main body and extending in the axial line direction of the rotary shaft and a second core including a second core main body disposed on the rotary shaft, and a plurality of second claw poles disposed in the edge portion of the second core main body and extending in the axial line direction of the rotary shaft and a third core including a third core main body disposed on the rotary shaft, a second elongation portion disposed in the center portion of the third core main body and extending in the axial line direction of the rotary shaft, and a plurality of third claw poles disposed in the edge portion of the third core main body and extending in the axial line direction of the rotary shaft, wherein the second core further comprises a surrounding member disposed in the center portion of the second core main body and surrounding the first elongation portion and the second elongation portion.

A stator includes a stator core having a yoke and a tooth, an insulator provided on the tooth, and a coil wound around the tooth via the insulator. The yoke has a first hole provided in an end surface in an axial direction of the stator core. The tooth has a second hole provided in the end surface. The second hole is provided at the center of the tooth in a circumferential direction of the stator core and arranged on a straight line passing through the first hole and extending in a radial direction of the stator core. The insulator has a first convex portion fitting into the first hole and a second convex portion fitting into the second hole.

A system for cryocooling an optical sensor on a satellite to a temperature below 200K with minimal vibration comprising a miniature conical rotary screw compressor comprising an inner element configured to only rotate around a first stationary axis and an outer element configured to only rotate around a second stationary axis so that both elements revolve with minimal vibration; with at least one of a) a length of at least one of the inner element and the outer element is between 10 mm and 100 mm; b) a diameter of at least one of the inner element and the outer element is between 2 mm and 45 mm; c) a compression ratio of the rotary screw compressor is between 1:2 and 1:20; and d) a shaft speed of the conical rotary screw compressor is between 1001 and 20000 revolutions per minute.

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 compressor includes a housing, a shaft that is rotated relative to the housing to compress a working fluid, and a foil bearing that supports the shaft. The foil bearing includes a top foil. The foil bearing is a foil gas bearing that is backed up by a ball bearing, or a mesh foil bearing with an actuator to compress a wire mesh dampener. A heat transfer circuit includes a compressor and a working fluid. The compressor includes a shaft that is rotated to compress the working fluid, and a foil bearing for supporting the shaft as it rotates.

A refrigeration cycle apparatus comprises: a refrigerant cycle circuit, a condenser, a pressure-reducing device and an evaporator are sequentially connected by pipes; an injection circuit that branches off from the refrigerant cycle circuit between the condenser and the pressure-reducing device and is connected to the injection flow passage; a flow rate control device provided in the injection circuit or the injection flow passage; and a controller configured to control the flow rate control device. At a time of starting up the compressor, the controller, controls regardless of a temperature of refrigerant discharged from the compressor, the flow rate control device so as to supply refrigerant liquid to the compression chamber via the injection circuit and the injection flow passage until an operating capacity of the compressor reaches a preset operating capacity or until a preset time elapses after starting up the compressor.