Research Article
Experimental Estimation of Journal Bearing Stiffness for Damage Detection in Large Hydrogenerators
Table 1
Main data of the generator upper (UJB), generator lower (LJB), and turbine (TJB) journal bearings.
| 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 | Assembled pad clearance at standstill | µm | 500 | 950 | 200 | Assembled pad clearance in operation | µm | 200 | 300 | 200 | Bearing preload | — | 0.933 | 0.925 | 0.994 | Pad pivoting system | — | Similar to rocker-pivot type | 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 viscosity at 100°C | Pas | 0.0068 | 0.0068 | 0.0068 | Lubricant density at 20°C | kg/m3 | 873 | 873 | 873 | Lubricant temperature range | °C | 40–55 | 40–55 | 40–50 |
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