Principle "220V Cooling Fan" operation is based on right-hand rule Ampere conductors through the current, generates a magnetic field around, if this conductor is placed in another fixed magnetic field, will generate attraction or repulsion, causing objects to move. DC fan blades inside, attached to a pre-filled with the magnetic rubber magnets. Surrounded by silicon, axial part of the winding two coils and a Hall sensor component as a synchronous detection device, controls a group of circuit which two coils wound around the axis of rotation job. "220V Cooling Fan" tachometer signal is generally output from the three-wire plug, three leads, yellow and black, respectively + 12V power and ground, another color of the line is the line speed signal output. It should be noted that some three-lead "220V Cooling Fan" of a third lead is not speed signal output line, but line speed control signal input speed control signal by which the DC fan motor.