Proposed is a lubrication system, in particular a single-duct minimum quantity lubrication system, having an aerosol generator, a spindle, a tool clamper arranged on the spindle and a rotary feedthrough arranged on the side of the spindle located opposite the tool clamper, the tool clamper, the spindle and the rotary feedthrough are penetrated by a duct, in the duct is arranged a spindle tube which improves the transport of aerosol, in particular the transport of lubricant particles and/or coolant particles, above all inside the spindle or motor spindle. Further, the spindle tube is mounted in the duct in an electrically insulating manner and/or in that the spindle tube is produced from a material that is not electrically conducting and/or in that the spindle tube and/or the duct is/are provided with at least one electrically insulating layer for coating the spindle tube and/or the duct in an electrically insulating manner.