METHOD AND APPARATUS FOR SYNCHRONIZING ROTATING MACHINERY TO REDUCE NOISE

A system for reducing noise created by multiple rotating machines by synchronizing the machines so as to establish a phase relationship between the machines which minimizes the noise. One or more feedback sensors, such as microphones, are placed so as to sense the noise to be reduced. The noise signals from the microphones are sent to a controller. Tachometer signals of the rotational speed of each machine are also sent to the controller. The controller generates an output signal in response to the inputs from the microphones and the tachometers that is fed to one or more of the rotating machines in order to establish the desired phase relationships.