Only the part code 245NQ015 appears in the name of this 94.4 KB PDF, suggesting a datasheet for a high current rectifier device rather than a circuit diagram. It sits alongside similar files numbered 240NQ to 249NQ. A technician would use it to verify electrical limits, terminal arrangement and mounting torque before swapping a failed unit. Any PDF reader opens it. Since the trailing digits usually change the voltage grade within such series, check the exact code on the device against the document.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.