| The frequency control allows FAD control of between 0% (idling) and the control range of 40 to 100 % with absorbed power of between 35 and 110 %. The part-load control is accomplished by changing the speed of the drive motor, which is controlled by a frequency converter.
If FAD drops to less than 40 % the compressor is working uneconomically. Depending on the switching cycle the compressor either switches off or continues in idle mode. The frequency control works most economically with oil-free screw compressors. |