When the generator is shut down for maintenance, the generator stator contains moisture. The stainless steel bellows on the generator stator water blowing device is connected to the flange interface at the upper end of the generator top through the reducing flange, and nitrogen is introduced to fill the generator stator with gas. After the gas pressure reaches 0.28 ~ 0.32MPa, the butterfly valve on the exhaust circuit is opened, and the gas pressure inside the stator is instantly released to discharge the moisture inside the generator stator through the gas pressure. Repeatedly add nitrogen into the stator of the generator, open the butterfly valve on the steam side, discharge the pressurized ammonia from the excitation side to the steam side to blow out the moisture, open the butterfly valve on the excitation side, discharge the pressurized nitrogen from the steam side to blow out the moisture. Repeated purging in this way can blow out the moisture inside the generator stator.