① Thrust bearing is overloaded and thrust pad is burnt out. ② Improper post-treatment after water hammer or steam humidity drop in the turbine. ③ Poor steam quality and fouling of the blades. ④ The unit suddenly sheds load or the medium-pressure cylinder valve suddenly closes by mistake. ⑤ Impurities enter the oil system and the oil film of the thrust pad is damaged.
The accident signs of thrust bush burnout are mainly manifested by large axial displacement, the temperature of the thrust pad and the oil return temperature increase, and the external characteristics of the machine like the thrust pad smoke.