Apple Inc.
Peripheral drive centrifugal fan

Abstract:

Electronic devices have peripheral drive centrifugal fans having smaller hubs and increased air flows to manage heat levels within the electronic device. A peripheral drive centrifugal fan includes a fan housing, an impeller including a plurality of blades, and a plurality of stacked inductor groups radially disposed about the impeller. Some of the blades have magnetically active portions. Each stacked inductor group includes first and second coils configured to impart a variable magnetic force to the magnetically active portion of a blade to drive the impeller along a rotational direction. The first and second coils can be selectively energizable independently from each other to provide greater control of the impeller.