Page 257 - Water Standards
P. 257

than ± 0   02mm. The deviation between two adjacent liner  s actual gap and
                   required value shall be no larger than 0   02mm. When the gap has been adjusted,
                   it shall be locked reliably.
               12  Installation of the generator  s temperature measuring devices shall meet the following
           requirements:
                 1) The temperature measuring device  s total insulation resistance shall be no less than
                   0   5MΩ. For a bearing which is required to be insulated, when all thermometers
                   have been installed, the insulation resistance of the bearing liner shall meet the
                   requirements of Table 4   2   8-7.
                 2) For the terminal blocks of the stator winding temperature measuring device, if
                   there is a discharge gap, the gap shall be between 0   3mm and 0   5mm.
                 3) Before the bearing  s oil groove is sealed off, the temperature measuring device
                   shall be checked and the difference between each resistance thermometer  s resist⁃
                   ances shall be no larger than 1   5%. The device shall be well insulated to ground.
                   The indicated value of the signal thermometer shall be close to the bearing liner  s
                   actual temperature. The lead wires used in measuring the temperature shall be
                   firmly fixed.
                 4) The mark number of the thermometers and temperature measuring switches shall
                   be in accordance with the number of lines and coolers and the slot number of the
                   windings.
               13  Installation of excitation systems and devices shall meet the following requirements:
                 1) The installation of the excitation system and devices shall meet the provisioons in
                   GB 10585 or GB / T 7409   3. The excitation system and devices shall only be in⁃
                   stalled when all interior construction has been completed and the indoor humidity
                   has met the relevant requirements.
                 2) For the excitation system plate or cabinet, the plug⁃in contacts of plug⁃in type
                   drawers shall be checked according to the design requirements.
                 3) Field discharge switch installation shall meet the following requirements:
                   —The opening/ closing coils and locking devices of the switch  s transmission
                    mechanism shall be checked separately and operational tests shall be also done.
                    The reliability and time of the operations shall comply with the relevant product
                    standards.
                   —Check if the action sequence of arc extinction contacts and main contacts are all
                    correct. The normally closed contacts shall act before the normally open
                    contacts and the spacing time after the breaking of the normally closed contacts
                    shall meet the design requirements.
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