DIY Knowledge

Fan wheel


Rodete de ventilador

Ventilateur à ailettes

The armature shaft of an electric motor carries the fan wheel which forces the circulating air to remove excess motor heat by ducted cooling. The fan power needed for this has to be supplied by the drive motor, and is associated as mechanical loss to the tool efficiency ratio. A considerable portion of the tool noise is produced by the fan wheel. BOSCH was capable of substantially reducing noise in electric power tools by means of the newly developed ultrasonic cooling fan. Its operating noise was limited to frequencies which the human ear cannot hear.