This is a remodeled version of the tower shaft from the MKIII Wind Turbine of 3dprintable1 ( https://www.thingiverse.com/thing:2851306 ). It is used if you do not intend to use a slipring and just wand to feed the cables through into the tower pole. The middle section still is preesent due to a combination of processing power of my PC and a not completely correct CAD command. Just delete it in your slicer. All credits go to 3dprintable1 for the original design, I only modified it to fit my needs