Backlash measuring method, wind turbine diagnosing method, and backlash measuring apparatus

A backlash measuring method using a controller having one or more processors for a wind turbine including a ring gear and a driving mechanism, the ring gear being fixedly attached to a first portion of the wind turbine, the driving mechanism being fixedly attached to a second portion of the wind turbine, the driving mechanism including a plurality of driving devices, each driving device having a pinion meshing with the ring gear, the driving mechanism being configured to rotate in a circumferential direction of the ring gear to drive the second portion relative to the first portion, the controller of the wind turbine being configured to measure backlash between a target pinion and the ring gear, the target pinion being the one of the pinions of the plurality of driving devices,

• the backlash measuring method comprising:
• a contacting step of bringing a target tooth of the target pinion into contact, at a tooth surface facing a first side in a rotation direction of the target pinion, with the ring gear, the target tooth being one of teeth of the target pinion;
• a rotation amount calculating step of (i) braking the ring gear relative to the second portion while the contact between the target tooth and the ring gear achieved in the contacting step is maintained, (ii) causing the target pinion to rotate toward a second side in the rotation direction opposite to the first side with a driving force less than a braking force applied to brake the ring gear relative to the second portion until the target tooth touches the ring gear at a tooth surface facing the second side in the rotation direction, and (iii) calculating an amount of rotation of the target pinion;
• and
• a measuring step of measuring, using the controller, the backlash between the ring gear and the target pinion based on the amount of rotation of the target pinion calculated in the rotation amount calculating step,
• wherein each driving device includes a brake unit configured to prevent rotation of the pinion,
• wherein, in the contacting step, while the target pinion is braked by the brake unit and a pinion other than the target pinion is free from braking by a brake unit, the controller of the wind turbine is configured to bring the target tooth into contact with the ring gear using an external force designed to rotate the second portion relative to the first portion.