System and method for protecting rotating shaft of crane driving mechanism

The invention relates to the field of hoisting machinery, and discloses a system and a method for protecting a rotating shaft of a crane driving mechanism. The system and the method for protecting the rotating shaft are different from a detection technology in the prior art that a motor and a winding drum need to be respectively provided with a position encoder, only a displacement measuring device needs to be installed on the winding drum, the rotation speed information of the motor is acquired from a servo drive of a servo motor, the rotation speed information of the motor is converted to the rotation speed of the rotating shaft of the winding drum, a theoretical traveling distance of the rotating shaft of the winding drum is obtained by integrating the rotation speed of the rotating shaft of the winding drum within a fixed period of time, the theoretical traveling distance is compared with the real traveling distance recorded by the displacement measuring device, when the difference between the theoretical traveling distance and the real traveling distance exceeds a preset warning value, a shaft broken accident can be determined, and a brake device is controlled to brake. The system and the method for protecting the rotating shaft of the crane driving mechanism have the advantages of low cost, high reliability and high detection accuracy and are applicable to a nuclear-grade device associated to the nuclear security.