A system for controlling a numerical control machine tool with movable component parts carrying tools andor mechanical component parts to be checked includes a control unit and a sensor device having an associated interface unit. If this input voltage exceeds a predetermined threshold voltage, the control unit switches in one or more loads. The braking receptacle is arranged in a space between a first surface formed on a part which rotates with the crushing head and a second surface formed on a non-rotary part which is connected to the frame bottom part. The reference power supply section obtains a voltage determined by dividing a potential difference between the power supply voltage VCC and the ground voltage GND by a predetermined dividing ratio as a reference voltage. The Mach cones are weakened by modifying exhaust gas flow in a longitudinal axial core of the exhaust gas streamtube.