Double inlet centrifugal fans, with and without flange, are used for air extraction in applications requiring high operating performance. These fans are equipped with a double shaft motor mounted on plastic supports, which minimise the transfer of mechanical noise generated by the rotation of the impeller and reduce the possibility of unbalance of the same. Voltage control can be used to modulate the rotation speed and the noise level of the double inlet fans. The double inlet fan motors are equipped with integrated thermal protection to protect them from damage and malfunctions.