Page 269 - Water Standards
P. 269

Table 4   2   13-1 (Continue)

             No      Item          Provisions          Explanation


                                                  (1 ) Before rotor assembly,
                                                 voltage tests shall be done ac⁃
                                                 cording to this specification; AC
                                                 voltage tests shall not be done
                                                 before  the  generator  unit  s
                                                 voltage has been raised;
                                                  (2) AC voltage tests shall be
                                                 done by phase. The starting
                                                 voltage should not be larger than
                                                 1 / 3 of the test voltage. The volt⁃
                                                 age shall be gradually raised to
                                                 the test voltage and the process
                               ( 1 ) Test voltage shall
                                                 should take about 10 to 15s;
                              be 0   8  times  the  test
                                                  (3) All the temperature re⁃
                              voltage in the factory;
                   Stator coil AC                sistances in the stator coils shall
             5                 ( 2 )  Corona  onset
                 voltage test                    be short circuited and grounded
                              voltage of the whole unit
                                                 before testing;
                              shall be no less than the
                                                  (4) Insulation resistance and
                              rated line voltage
                                                 polarization indices  shall  be
                                                 measured and the DC voltage
                                                 test shall be done before the
                                                 test;
                                                  (5) During the voltage tests,
                                                 there shall be no obvious golden
                                                 light spots and connected corona
                                                 belts at the stator ends under the
                                                 rated line voltage. When the ele⁃
                                                 vation is above 1000m, the
                                                 starting voltage shall be revised
                                                 according to JB / T 8439


               2   The items and requirements of rotor coil tests shall meet the provisions of Table
           4   2   13-2  


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