Compressor

A compressor comprises a rotor assembly 4, a stator assembly 6 and a heat sink assembly 5. The rotor assembly comprises a shaft to which an impeller, a bearing assembly and a rotor core are secured. The bearing assembly comprises a pair of bearings. The heat sink assembly comprises a sleeve to which a heat sink is secured. The bearing assembly is located between the rotor core and the impeller, the sleeve is secured to the bearing assembly, and the heat sink is secured to the stator assembly. The heat sink may comprise a plurality of legs that extend radially from the sleeve, with the stator assembly secured to one or more of the legs. The heat sink assembly may be glued to the stator assembly. In a method of assembling the compressor the heat sink assembly, bearing assembly and stator assembly may be assembled into a collective assembly, which is subsequently secured to a frame 2 of the compressor. The frame may comprise a diffuser, wherein the impeller is aligned with the diffuser when the collective assembly is secured to the frame.