Page 258 - Water Standards
P. 258
—When a DM type field discharge switch is used, the amount, arrangement,
shape and installation position of the arc extinction grid s plates, shunt
resistor s connection and resistance and arc extinction contact s spacing shall be
checked. All of them shall meet the product and ordering requirements
4) The laying and wiring of excitation system cable shall meet the following require⁃
ments:
—The lengths of the three⁃phase power cable which connects the excitation trans⁃
former with the power cabinet shall be equal.
—Cable laying and internal wiring shall meet the requirements in GB 50168 and
GB 50171
4 2 9 Horizontal hydraulic generator installation shall meet the following requirements:
1 Bearing liner scraping shall meet the following requirements:
1) The bearing liner and mirror plate shall be checked according to the requirements
of Article 4 2 8 of this specification. The bearing liners which are required by the
manufacturer to be scraped on the work site shall be processed in two steps, i e.
initial scraping and fine scraping. The initial scraping shall be done before putting
the rotor onto the stator and the fine scraping shall be conducted after centering the
rotor.
2) The scraping of the pedestal bearing liner shall meet the following requirements:
—The gap between the bearing liner and the shaft neck shall meet the design re⁃
quirements. Gaps on the two sides shall be one half of the top gap, and the
difference between the gaps on the two sides shall be no larger than 10% of
the gap.
—The contact angle between the bearing liner bottom and the shaft neck shall
meet the design requirements and shall be no larger than 60°. The bearing liner
shall be totally and uniformly contacted along the direction of its length. There
shall be 1-3 contact points per square centimeter in the contact area.
—For bearings which adopt pressure oil circulating lubrication systems, the oil
gallery size shall meet the design requirements and the head s length on two
ends of the lengthways oil gallery at the joint shall be no less than 15mm
3) Scraping of thrust pads shall meet the following requirements:
—The contact area between the thrust pad and thrust collar shall reach
75 % of the total area and there shall be 1 - 3 contact points per square
centimeter.
—The thickness of thrust pads without adjusting devices shall be equal. The
thickness difference between each thrust pad in the same group shall be no lar⁃
ger than 0 02mm
2 The allowable installation error of the bearing seat shall meet the requirements of Ta⁃
2 5 1