Experimental Estimation of Journal Bearing Stiffness for Damage Detection in Large Hydrogenerators

Table 4

Original and estimated bearing effective stiffnesses of the upper journal bearing ( = 1.18 GN/m) of a 700 MW hydrogenerator, using synthesized shaft and bearing vibration signals.

Condition	Original bearing stiffnesses [GN/m]			Simulated shaft vibrations [µm]		Simulated bearing vibrations [µm]		Estimated effective stiffnesses [GN/m]
	1	6.67	0.00	6.67	4.3	4.3	24.5	24.5	6.72	6.72
2	3.33	0.00	3.33	9.3	9.3	26.5	26.4	3.36	3.35
3	1.11	0.00	1.11	30.6	30.3	29.1	28.8	1.12	1.12
4	3.33		1.11	9.7	32.5	26.1	29.5	3.18	1.07
5	3.33		3.33	9.7	10.2	26.5	26.7	3.22	3.09