Must convert "220V AC Cooling Fan" heat that is the temperature difference (DT) converts heat to offset the number of (W) Watt heat required to remove air volume (CFM) of the total cooling requirements are very important for the effective operation of the system. Efficient operation of the system must provide the ideal conditions to make components for all "220V AC Cooling Fan" in the system can maximize the function and the longest life. The following are several ways you can use to select the general use of the fan motor: the heat generated inside the device calculated decision "220V AC Cooling Fan" can allow the internal temperature rise range. Calculate the required air flow volume from the formula. Estimating apparatus used by the system impedance. According to the characteristic curve or directory specification to select the desired fan