"220V Cooling Fan" Speed is the number of revolutions per minute of the fan blades, the unit is rpm. Fan speed is determined by the motor inside the coil turns, voltage, number of fan blades, angle, height, diameter and bearing systems. Fan speed and quality are not necessarily linked. Fan speed can be measured by the internal speed signal, it can also be measured by the external. With the application and ambient temperature changes, and sometimes we need different speed "220V Cooling Fan" to meet demand. Some vendors specially designed adjustable fan speed cooling fan, manual and automatic modes. Manual is designed to allow users to use low speed in winter to obtain a low noise, high speed to get a good cooling effect in the summer. Automatic class radiator thermostat with a thermostat sensor generally, according to the current working temperature control "220V Cooling Fan" speed, speed is increased by high temperature, low temperature, then reduce speed to achieve a dynamic balance, so that the cooling effect of wind noise and to maintain an optimal combination of points.