The frequency converter, as a part of the internal vibrator for the compaction of wet concrete, is positioned as an electrical component between the power cable and the conduit. With its line management and swelling body in the flow direction, it refers to the function of increasing the current frequency. Due to its rejuvenation to the size of the cable, the cable will not be trapped, which improves the handling significantly. The protruding ribs provide stiffness, protect the power switch and facilitate the transport.