HYDRAULIC MACHINE WITH DIAGNOSIS SYSTEM, RENEWABLE-ENERGY TYPE POWER GENERATING APPARATUS AND METHOD FOR DIAGNOSING HYDRAULIC MACHINE

A diagnosis system for a hydraulic machine which includes a rotor shaft, a cylinder, a piston forming a working chamber together with the cylinder, and a high-pressure valve and a low-pressure valve provided for the working chamber, and which is configured to perform conversion between rotational motion of the rotor shaft and reciprocal motion of the piston. At least one of the high-pressure valve or the low-pressure valve includes a solenoid valve which includes: a valve body configured to be attracted toward a core by a magnetic force generated by supplying electric current to a coil; and a position restricting part for restricting a position at which the valve body is closest to the core when attracted. The diagnosis system includes: a pressure sensor for detecting a pressure of the working chamber; a response-delay calculating part configured to calculate a response delay which is a period of time from a point of time when supply of electric current to the coil is stopped to a point of time when the valve body separates from the core, on the basis of a temporal change in a cylinder pressure obtained by the pressure sensor; and a damage detecting part configured to detect a damage of the position restricting part on the basis of the response delay.