To supply electric power to an auger without providing a control board and without enlarging the size of a generator.
In the power generation device of an earth auger machine driven by an electric motor such as an auger screw, an open phase and reverse phase detector 14, a normal rotation and reverse rotation switch 15 and a pole number switch 16 are provided to be connected between a breaker and an output terminal board 35 in the casing of the power generation device in series, and a resistor 27 for desired voltage reduction at the time of short circuit and a relay 28 for short-circuiting the resistor 27 for a prescribed time at the time of the starting of the electric motor are provided between an automatic voltage regulator 21 and a voltage increase and decrease device 30.
MATSUYOSHI ATSUKI
YOSHIDA ICHIRO
WASHIZU MANABU