Fan motors are commuted electronically; therefore, a high level of rotational speed stabilisation is obtained. Sensors operated based on the Hall phenomenon monitor the operation of the fan. Their feedback is directed to the processor where it is compared with the set value. If there is a difference between the signals, the feedback and the set one, rotational speed is corrected. The stabilisation of the fan operation is also affected by a temporary value of power supply current, which a sudden increase in airflow resistance in the installation, the ongoing corrections of voltage and current values result in the more stable and fan operation conditions, and they stabilise the airflow.