Rotor Jacking
Large frame-sized turbines found in utility scale steam‚ combustion and combined cycle power plants use high-pressure hydraulic oil pumps to lift the turbine shaft from its sleeve bearings before the turbine is started. Hot turbines that are being shut down are put on “turning gear” drive. This allows the turbine to rotate very slowly while it cools so its shaft does not sag due to its weight. A hydraulic oil motor drives a gear which maintains this slow rotation of the turbine shaft.
When evaluating a pump for this application‚ ensure that the pump and inlet piping are properly sized to handle cold start conditions because lower temperature affects the viscosity of the lubrication oil and Net Positive Inlet Pressure Available (NPIPA). The lift capability of a pump decreases with temperature.
Suitable pumps here are three screw and crescent internal gear pumps.
| Flow Rates up to | Pressures to up to | Max Fluid Temperature | CIRCOR Brand‚ Series & Pump Type |
| 13 m^3/h 55 GPM | 210 bar 3‚046 psi | 80C 176F | Allweiler SD Three Screw |
| 28 m^3/h 125 GPM | 345 bar 5‚000 psi | 82C 180F | IMO CIG Crescent Internal Gear |
| 91 m^3/h 400 GPM | 151 bar 2‚200 psi | 120C 250F | IMO 12D Three Screw |