Page 250 - Water Standards
P. 250

to work reliably and send warning signals correctly  
           4   2   8  Installation of vertical hydraulic generators shall meet the following requirements:
               1  The scraping of the bearing liner shall meet the following requirements:
                 1) The thrust pad shall have no flaws such as fissures, slag inclusions or dense
                   pores. The total area of localised exfoliation of the bearing liner surface material
                   and metal base shall be no larger than 5% of the liner surface area. If necessary,
                   ultrasonic inspection may be used to check the thrust pad. The working surface of
                   mirror plates shall have no scar or rust. The roughness and stiffness shall meet the
                   design requirements. If necessary, the parallelism between two surfaces and the
                   working surface flatness shall be checked according to the drawing requirements.
                 2) Thrust pads which the manufacturer requires to be scraped on the work site shall
                   meet the following requirements after scraping:
                   —There shall be 1-3 contact points per square centimeter on the liner surface.
                   —On the liner surface, the area of each local non⁃contacting part shall be no lar⁃
                    ger than 2% of the bearing liner  s total area and the total non⁃contact area shall
                    be no larger than 5% of the bearing liner total area.
                   —The inlet shall be scraped according to the manufacturer requirements.
                   —For supporting screw type thrust bearings without trays, only when its liner has
                    met the above requirements can the middle part of the liner surface be scraped.
                    In the vicinity of the supporting screw in a circular section whose diameter is 2/
                    3 of the bearing pad length, first remove contact points ( light contact points
                    can be preserved) and cut the bearing pad once with a gang cutter. Secondly,
                    cut the bearing pad in a smaller range, with a gang cutter again, in the
                    vicinity of the supporting screw in a circular section whose diameter is 1/ 3 of
                    the bearing pad length and in a direction perpendicular to the previous cut.
                   —After barring of the generator unit, the thrust pad shall be extracted to check
                    the degree of contact. If the liner has been rubbed down or there are linked
                    points, the liner shall be scraped again until it is qualified  
                 3) The scraping of the guide bearing liner shall meet the requirements of Article
                   4   2   3 in this specification.
               2  The stator  s allowable installation error shall meet the requirements of Table 4   2   8
           -1.






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