FAN APPARATUS, ELECTRONIC APPARATUS, AND CONTROL METHOD FOR THEM

摘要

A fan (43) is structured as a centrifugal fan. A rotation speed detecting circuit (65) detects the actual rotation speed of the rotor (44). A deviation detecting circuit (69) detects the deviation between the actual rotation speed and a designated rotation speed specified in a control signal supplied to the fan (43). The deviation detecting circuit (69) generates a predetermined signal if the actual rotation speed exceeds the designated rotation speed by a predetermined deviation. The inventors have revealed that the occlusion of the ventilation opening of the fan (43)induces the rotor (44) to rotate at the actual rotation speed exceeding the designated rotation speed if the fan (43) is structured as a centrifugal fan. The deviation detecting circuit (69) detects the deviation between the designated rotation speed and the actual rotation speed. The occlusion of the ventilation opening, namely the accumulation of dust at the ventilation opening can be detected in a facilitated manner based on a signal supplied from the deviation detecting circuit (69).