Using Simplified Models to Assist Fault Detection and Diagnosis in Large Hydrogenerators

Table 6

Simulated shaft and bearing vibrations at upper (UJB), lower (LJB), and turbine journal bearings (TJB), with the LHG at speed-no-load (SNL) or excited, with generator rotor unbalanced (ISO grade G4.25).

Clearance condition	1x shaft relative vibrations [m peak]						1x bearing absolute vibrations [mm/s peak]
	UJB		LJB		TJB		UJB		LJB		TJB
	Dir. X	Dir. Y	Dir. X	Dir. Y	Dir. X	Dir. Y	Dir. X	Dir. Y	Dir. X	Dir. Y	Dir. X	Dir. Y
A (SNL)	3.8	3.8	7.2	7.2	3.1	3.1	0.22	0.22	0.14	0.14	0.10	0.10
(SNL)	2.2	3.1	4.6	6.2	3.0	3.1	0.22	0.22	0.15	0.14	0.09	0.09
B (SNL)	7.2	9.2	12	14	3.4	3.6	0.24	0.24	0.13	0.12	0.11	0.11
B (excited)	10	13	16	20	4.0	4.3	0.32	0.35	0.17	0.16	0.12	0.13
C (excited)	29	55	36	59	5.5	6.9	0.40	0.50	0.16	0.17	0.17	0.21
D (excited)	19	57	25	61	4.8	7.0	0.35	0.51	0.16	0.17	0.15	0.21

The symbol “”indicates that the shaft position is different. In the clearance condition A the pad clearances are in the nominal values (200 µm) and the shaft is centered at coordinates (0,0). In clearance condition A* the pad clearances are once more in the nominal values but the shaft has an eccentricity of 67 µm.