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1. Steam turbine of 350MWe. There is 20Ton HP rotor, 60 ton IP rotor, 60 ton LP rotor and 60 ton generator rotor.
2. The thrust bearing is Kingsbury type and installed at front bearing of HP Turbine in front pedestal.
3. We uncoupled the HP-IP rotors, while IP,LP and Generator rotor remained coupled. We created a gap between HP and IP rotor about 8mm so that we can measure the thrust clearance by only pull/push HP rotor which was about 0.34mm thrust clearance.
4. After measurements of thrust clearance, we pushed the HP rotor towards active end by 50 ton jack.
5. We pushed IP-LP-Generator rotor train towards the HP coupling to end 8mm clearance which was earlier created to measure thrust. It is to be mentioned that that there is design bottom gap between HP-IP coupling face of about 0.20mm.
6. During coupling rotor were physically on the journal bearings, meaning no jacking oil was available for HP,IP,LP, Generator rotor (no provision available from OEM to take JOP during coupling)and outage day is 40. Means no oil in the bearings.
7. After coupling, HP rotor axial position changed to 0.25mm as compared to the uncoupled condition.
8. What is the root cause?
2. The thrust bearing is Kingsbury type and installed at front bearing of HP Turbine in front pedestal.
3. We uncoupled the HP-IP rotors, while IP,LP and Generator rotor remained coupled. We created a gap between HP and IP rotor about 8mm so that we can measure the thrust clearance by only pull/push HP rotor which was about 0.34mm thrust clearance.
4. After measurements of thrust clearance, we pushed the HP rotor towards active end by 50 ton jack.
5. We pushed IP-LP-Generator rotor train towards the HP coupling to end 8mm clearance which was earlier created to measure thrust. It is to be mentioned that that there is design bottom gap between HP-IP coupling face of about 0.20mm.
6. During coupling rotor were physically on the journal bearings, meaning no jacking oil was available for HP,IP,LP, Generator rotor (no provision available from OEM to take JOP during coupling)and outage day is 40. Means no oil in the bearings.
7. After coupling, HP rotor axial position changed to 0.25mm as compared to the uncoupled condition.
8. What is the root cause?
