Experimental Aspects in the Vibration-Based Condition Monitoring of Large Hydrogenerators

Table 1

Main data of the generator upper journal bearing (UJB), generator lower journal bearing (LJB), and turbine journal bearing (TJB).

Symbol	Description	Unit	UJB	LJB	TJB
	Number of pads	—	16	16	12
	Journal radius	mm	1100	2600	1600
	Bearing pad radius	mm	1103	2604	1633
	Journal speed	m/s	10.6	25.1	15.5
	Nominal pad clearance at standstill	µm	500	950	200
	Nominal pad clearance in operation	µm	200	300	200
	Bearing preload	—	0.933	0.925	0.994
	Distance trailing edge, pivot	mm	140	248	250
	Pad length	mm	350	620	500
	Pad width	mm	400	310	500
	Pad mass	kg	172	290	390
	Bearing direct stiffness (average)	GN/m	6.70	2.85	6.70
	Bearing global stiffness	GN/m	0.80	1.25	1.45
—	Lubricant type		Lubrax Turbina Plus 50
	Lubricant viscosity at 40°C	Pas	0.047	0.047	0.047
	Lubricant density at 20°C	kg/m^3	873	873	873
	Lubricant temperature range	°C	40–55	40–55	40–50