Patent ID: 8356983

Claim:
An apparatus for controlling an air distribution system of the type which includes a duct system, a motor drivingly associated with a blower and a target air flow rate signal which represents a target air flow for the air distribution system, the apparatus providing control of the motor speed to maintain a rate of air flow in the system at substantially the target air flow rate, characterised in that the apparatus comprises: a microprocessor means to determine a target frequency and supplied voltage signal in response to a combination of one or more of the following: speed signal, load signal, provisional frequency signal, target air flow rate and target motor revolution signal, whether received, sent or calculated by the microprocessor for setting the air flow rate according to the target air flow rate; a controller means to control a supplied frequency to the motor to achieve a provisional frequency specifying a particular frequency of the motor, and to control the supplied voltage signal, supplied to the controller means from an air flow control module, to achieve a provisional voltage signal; another controller means to receive the target air flow and provide the target air flow to the microprocessor; sensing means to detect a speed signal representative of the speed of the motor and means to provide the speed signal to the microprocessor; another sensing means to detect the load signal representative of the load of the motor and means to provide the load signal to the microprocessor; means for calculating a slip signal by using the speed signal and the frequency signal; and wherein the air flow control module controls the supplied voltage signal in response to the slip signal.