4.3.3.7 Bearing Temperatures – Firs

4.3.3.7 Bearing Temperatures – First Article Tests shall determine the temperature rise of the generator bearings. Temperature differential between oil bath and bearing lining shall be established for sleeve type bearings. Acceptable temperatures must meet application requirements and lubrication limits. This test may be waived if bearing temperature detectors are not purchased and it is not possible to make this measurement by other methods. 4.3.3.8 Bearing Support Stiffness – First article tests shall verify the supplier’s calculated stiffness value by measuring the stiffness of each bearing support in both vertical and horizontal directions while the shaft is supported by a hydro-dynamic oil film. Either driving point modal impact measurements or operating run-up, coast down conditions can be used in the extraction of the bearing support stiffness. Irrespective of the methodology used to extract bearing support stiffness, measurements should be made in the 0-65Hz range. Bearing housing stiffness should be presented for both bearing housings, in the vertical and horizontal direction. A FE model of the bearing support structure to extract the housing stiffness is suggested.