To provide a low-cost cutter motor driving device for a tunnel excavator and a method for it causing no disturbance in the case of a failure of an inverter.
This tunnel excavator is provided with a cutter head turning by using a cutter turning motor as a driving source, a supporting board supporting the cutter head freely rotationally, a base arranged behind the supporting board, and a plurality of pairs of thrust jacks arranged between the supporting board and the base board to be expanded/shrunk for drilling the ground. The cutter driving motor is constructed of a plurality of inverter control motors and a plurality of polarity changing type motors. In the inverter control motor, an inverter control circuit 55 having opening/closing switches arranged on the input side and the output side is connected, and a bypass circuit 60 bypassing the opening/closing switches is arranged. An opening/closing switch is also arranged in the circuit of the polarity changing type motor. In this way, motor driving by inverter control, polarity changing type motor driving, and a combination of them can be realized.
OKAMOTO KAZUYUKI
TANIMOTO KIMIMASA
