5.9　Excitation Device

5.9.1　The inspection and installation of an exciter with AC brushless excitation system shall comply with the following provisions in addition to the relevant specification for an air-cooled generator:

1　The inside of the hollow base of an enclosed ventilation excitation device shall be clean and free of sundries such as welding slag or dust，and its air filter shall be filled with element dipped with clean and viscous oil and without oil dropping.

2　The bolts for exciter bearing cover shall be tightened homogeneously and provided with lock washers.

3　The main pole and rectifier pole shall be in close contact with casing without looseness，and the bolts shall be locked.

5.9.2　During installation，a self-excitation static excitation device shall be checked as follows and comply with specification:

1　For the bearings of excitation device，the bearing pad top clearance should be 2/1000 of the shaft diameter，and the clearance on one side shall be 1/1000，but must not be less than 0.10mm for a journal with diameter less than 100mm，and the feeler gauge insertion depth shall be 15mm-20mm when measured；for an excitation device journal with flange shoulder，the axial clearance between machine side shoulder and bearing pad shall be greater than the maximum extension of shaft system expansion.

2　Before connection of couplings，the insulation resistance value between the shaft and base after connection of oil baffle and shaft shall be measured with a 1000V megohmmeter，and it shall be greater than 0.5MΩ.

3　The clearance of collector ring，carbon brush box and excitation device rotor shall comply with manufacturer requirements，the axial clearance from rotor shoulder shall meet the provision for thermal expansion of the unit.

5.9.3　The excitation device rotor shall be checked before installation and comply with the following provisions:

1　For the excitation device rotor directly assembled at the generator shaft end，the coupling bolts shall be tightened to the torque required by manufacturer，and the shaft head run out at the end of its cantilever shall not exceed the value required by manufacturer.

2　For the excitation device rotor supported by only one bearing，after the shaft head run out has been adjusted，the supporting bearing can be raised according to manufacturer requirements；when load jacking test is specified，the load to jack the shaft end of excitation device rotor shall be 1/2-3/4 the weight of the excitation device rotor，and the shaft end lifting height shall not exceed 0.03mm.

3　For the rotor of excitation device of a dual internal water cooled generator，the central water passage hole shall be clean and free of sundries.