Page 268 - Water Standards
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Table 4   2   13-1  Items and provisions of stator installation tests

             No      Item          Provisions          Explanation
                                 Both the standby coils
                   AC voltage test
                              and self⁃made coils shall
             1   of     single                            —
                              meet  the  equipment
                 stator coil
                              supplier requirements
                               (  1  )   Insulation
                              resistance, absorptance or
                              polarization  indices  shall
                   Stator coil in⁃
                              meet the requirements of
                 sulation
                              Article 4   2   8 in this speci⁃    Use a megohm meter with a
             2   resistance,
                              fication;          test voltage of above 2500V
                 absorptance  or
                               (2) Each phase unbal⁃
                 polarization index
                              anced insulation resistance
                              coefficient shall be no larger
                              than 2
                                                  ( 1 ) Measure in the cold
                                                 state. The temperature difference
                                Direct current resistance  s  between coil surface and sur⁃
                              deviation between coil phases  rounding air shall be no larger
                              and branches shall be no  than 3℃;
                   Stator coil  s di⁃
                              larger  than  2%  of  the  (2) When using the voltage
             3   rect current re⁃
                              minimum value among them  drop method, the current shall
                 sistance
                              when the deviation has been  be no larger than 20% of the
                              adjusted for that caused by  rated current;
                              wire length difference  (3) If the test results exceed
                                                 the  requirements  above, the
                                                 reasons shall be determined
                               (1) Test voltage shall be  (1) Tests shall be done in
                              3 times the rated line volt⁃  the cold state;
                              age;                ( 2 ) Test voltage shall be
                               (2) The leakage current  raised step by step. Increase the
                   Stator coil DC  shall  not  increase  with  rated voltage by 0   5 times in
                 voltage test and  time;         each step and hold for 1 min.
             4
                 the leakage cur⁃  ( 3) Under the required  Read the leakage current in each
                 rent         test voltage, the difference  step;
                              between  each  phase  s  (3) If the results cannot meet
                              leakage current shall be no  the  requirements  above,
                              larger than 50% of the min⁃  problems shall be found out
                              imum value         and resolved

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