Compressor control system and method for controlling the same

1. Field of the Invention The invention relates to a method for controlling a compressor installation with at least one lubricated screw-type compressor element () connected to a pressure vessel () which is driven by an electric motor () which is regulated in function of the compression pressure, and which compresses the gas supplied through the gas inlet conduit (). The return flow of lubricating agent through the return conduit () also is determined by a controlled valve () which is provided with a calibrated opening () and which is controlled by control means () which, as the number of revolutions of the screw-type compressor element () has dropped below a well-defined value, put the controlled valve () into the position in which it restricts the return flow of lubricating agent to a flow through the calibrated opening ().