Importance

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Abstract

A fan for mounting on and use in connection with cooling of components on a PWB comprising a PWB having an aperture therein for receiving a bearing holder with a bearing rotatable within the holder. An annular multipole permanent magnet is secured to the bearing for rotation in the bearing holder. An impeller in the form of radially and outwardly extending vanes, aligned with a central point but spaced from said point, is secured to an outer surface of the permanent magnet and rotates therewith. A housing is secured to the PWB, the housing being disposed over the impeller and the magnet and having two openings, one in the region above the central point of the vanes and a second opening facing along the surface of the PWB. Four electromagnets are secured to the side of the PWB opposite the magnet, the electromagnets being positioned at the four corners of a square and beneath the magnet. A nonmagnetic spacer surrounds the electromagnets with a stator positioned thereover and beneath the electromagnets, the stator being secured to the bearing holder by means of a threaded member. The electromagnets are pulsed serially by a pulse circuit disposed on the surface of the PWB, the pulses being applied to the electromagnets via conductive paths of the PWB.

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First Claim