Process and device for flow control of an electrical motor fan

摘要

A method and configuration from maintaining a constant of air to a protective helmet ( 4 ) from a fan ( 3 ) in a battery powered fresh air unit. The fan ( 3 ) is a radial fan with a filter ( 5 ) positioned on the suction side of the fan and is operated by a brushless continuous current motor ( 2 ). With the aid of signals from position sensors ( 30 ) in the motor ( 2 ), a control unit ( 12 ) can determine the speed of the fan ( 3 ). The control unit also detects the motor's power consumption and compares this and the speed with a characteristic curve for the motor ( 2 ) for a given flow from the fan, which is stored in a memory ( 14 ). In the event of any deviation, the control unit ( 12 ) regulates a change of the voltage supply to the motor ( 2 ) so that the deviation is reduced.