An apparatus for controlling the performance of a blower motor for a vacuum cleaner

Apparatus for controlling the power of a fan motor (24) for a vacuum cleaner (10) which are arranged one in a dust space (20) replaceable filter bag (22), characterized by - a pressure sensor system (30; 30 ') for detecting a differential pressure between an in Saugstromrichtung before changing filter bag lying (22) first portion and lying in a Saugstromrichtung after changing the filter bag (22) and the second region - a control unit (26) for the blower motor (24), but which adjusts the power of the fan motor (24) in dependence on the detected differential pressure independent of the vacuum in the first region.