A centrifugal blower is provided which incorporates a self-contained air cooling system. The blower includes a drive assembly connected to a drive motor and disposed within a housing having inlet and outlet apertures. A centrifugal compressor is connected to the drive assembly and disposed exteriorly to the housing adjacent to the outlet apertures. Rotation of a drive pulley, including a fan, by the drive motor causes air to enter the housing through the inlet apertures, flow over components of the drive assembly, and exit through the outlet apertures. A spindle assembly having a rigid bearing arrangement is also provided. One or more bearing elements are disposed at opposite ends of a spacer and between a shaft and housing of the spindle assembly. Such rigid pre-loaded bearing arrangement eliminates "unloading" concerns, and allows load sharing between bearing elements.