US Patent 7239968 Method and apparatus for predicting fan failure

A method and apparatus are provided for monitoring and adjusting angular speed or rotational frequency of a fan as well as wear. As a result of being able to monitor the angular speed or rotational frequency of a fan, a prediction of both wear and failure can be made. Due largely to increasing internal friction related to the amount of wear, the energy required to operate a fan at a given angular speed or rotational frequency varies. Hence, an algorithm and certain devices can be employed to make wear and failure predictions of either an mechanical or electrical fan based on energy consumption relative to an angular speed or rotational frequency.