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

Table 5

Original and estimated bearing effective stiffnesses of the lower journal bearing ( 2.22 GN/m) of a 700 MW hydrogenerator, using synthesized shaft and bearing vibration signals.

Condition	Original bearing stiffness [GN/m]			Simulated shaft vibrations [µm]		Simulated bearing vibrations [µm]		Estimated effective stiffness [GN/m]
	1	2.86	0.00	2.86	10.0	10.1	13.1	13.2	2.91	2.90
2	1.43	0.00	1.43	17.2	17.1	11.2	11.2	1.45	1.45
3	0.48	0.00	0.48	36.9	37.1	7.9	7.9	0.48	0.47
4	1.43		0.48	17.2	38.4	11.1	7.9	1.43	0.46
5	1.43		1.43	17.4	18.0	11.2	11.0	1.43	1.36