Once the size of the cooling fan is determined, measure the pressure value corresponding to each voltage or speed under different air flow, and then draw a P-Q curve as shown in the figure below. This curve can be used to describe the characteristics of the fan, so it is called the cooling fan characteristic curve. It is used to test the air pressure, air volume specifications and characteristics of the cooling fan, It is mainly conducted in accordance with the "Laboratory Method of Testing Fans for Rating" test specification of American Air Movement and Control Association (AMCA) No. 210-85. The measured characteristic curve is generally called P-Q curve. P-Q curve is generally described by three physical values:
P-Q curve
(1) Pmax: when the air volume is 0, the maximum static pressure value of the fan under the fixed volume state of a confined space.
(2) Qmax: the flow when the pressure difference between the inlet and outlet of the fan is 0, which is the maximum flow of the fan.
(3) P-Q value: the corresponding value of the pressure difference between the inlet and outlet of the fan and the flow Q under the current state.
