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Operating Guidelines for D11/D12 Steam Turbines Equipped with Enhanced ATS Controls 3000/3600 RPM Units

If the turbine fails to come off turning gear with the valves more than 5% open, immediately TRIP the unit and investigate. When starting with new shaft packing or after a maintenance shutdown, it is advisable to “sound-out” the machine. During acceleration to the low speed hold point, listen for audible sounds of internal rubbing. If sounds are evident, decrease the turbine speed to zero rpm and place the turbine on turning gear for 2 to 4 hours before attempting another start. Observe that shaft eccentricity has returned to normal before a restart attempt. Should bearing vibration levels exceed trip limits, place the turbine on turning gear for 2 to 4 hours before attempting another start. If the high vibration levels persist, refer to GEK 89610 “Rotor Vibration” in the unit’s instruction book and GEK 107588 “Operation to Maintain Radial and Axial Clearances”. Should vibration levels continually exceed trip limits, contact and consult with a GE service representative.