Many people "24V DC Cooling Fan" are not very understanding, in fact, the operation of DC fan with the heat of the case is changed to a slower speed operation, the fan will have less noise and consumes less energy. In most of the design requirements, after "24V DC Cooling Fan" speed operation is usually lower than the temperature of the air for several hours maximum design temperature value. Under normal circumstances, low speed cooling fan can be enough to complete its work. When the fan is temperature changes slowly, "24V DC Cooling Fan" slower rate of change will not suddenly change the fan speed and noise. The reaction time depends mainly on the length of the sensor of its thermally-induced sensitivity.