Inventors:
Norman H. Holzhauer - Aberdeen NJ
Assignee:
AT&T Bell Laboratories - Murray Hill NJ
International Classification:
G08B 2100
Abstract:
A pressure transducer, such as a microphone, is placed in proximity to the blades of a fan, such as a fan used to cool electronic equipment. As each blade passes the transducer, a pressure wave is generated that is converted into an electrical pulse by the transducer. Circuitry responsive to those pulses signals an alarm if the fan is not operating properly.