Steam Turbine Won't Rotate

You need to take it apart and clean it out. It is probably full of corrosion or debris.

And after five years you are supposed to check for balance. You are most likely to have the rotor sagged.

What happened to basic procedure of regularly rotating the rotor ? We ask even the spare rotor (un assembled) to be rotated periodically in its supports.

Former Navy snipes I have worked with have told me that regarding the prop shaft that on the Midway they had to manually rotate the shaft back and forth to prevent damage on start up due to shaft sag ( you wouldn't believe how much spam I get offering to rectify that problem) and on the nukes they have to leave the shaft slowly rotating while in port.

Does the unit have a separate input that would allow the application of rotational force, independent of the steam motive force?

Or the lack of lubricating during shutdown has allowed the bearing to come into contact with the rotating surface and has stuck from either developing a "suction" or a reaction between the dissimilar materials creating a thin, congealed lubricant/corrosion product "glue".

My guess is also that it has sagged and now its so bad that there is contact between the rotor and the stator (if thats the right name) blades.

It needs to be taken down/apart and a new shaft installed (assuming that it has not also rusted solid in the 5 years.......new bearings if ball type or similar.

Basically it must be fully reconditioned.......by the maker is often the best way....

Even if it had run up, it would probably have shaken itself apart within a few minutes.....maybe killed a few bystanders at the same time!!!

start your oil pump, check oil flow and engage the turning gear. Does it turn it? Measure the turning gear motor current. Crack steam open and heat the turbine slowly.

If turning gear turns it then minimum you need to inspect the bearings before starting.

absolutely.

my dear turbine rotor is rotating in its housing an producing power with out opening the turbine casing thanks for consultation

Thank you for an update. Could you be so nice and briefly describe works done before machine start up?

We know that rotor was lifted by 0.2 mm. Is it all what you did?

There is no doubt that after five years the rotor has bowed (sagged). That is why you have a turning gear on this style machine. But 6.2 MW turbine will not sag enough to lock it up, enough to cause very high vibrations on startup, but not enough to lock it up.

There must be crap and corrosion in the interstage labys. You can try to force it to turn as has been suggested, and it might even work, but all that stuff has to go somewhere and it is not good for the machine.

Bottom line is you have to open it up and overhaul the turbine.

By the way, good answer squpek

You need to check the turbine journal bearings as well. After 5 yrs you will most likely shred the babbit in the bearings once the turbine starts to move. I agree with all of the folks above: a complete turbine overhaul is in order.

my dear bearings are in very good condition. and there is no wear on bearings. roter was stucked on active side of thrust bearing. now i tel you what we did? we opened the both bearings and checked the axial movement there was no axial move ment so we removed the both radial bearing and lift the turbine rotor 0.1 mm by adding shims on bottom adjusting segment. then we try to move it axially after removing thrust bearing. it moves axially 0.45mm . after that we try to turn it but failed. so we decided to lift the rotor0.1mm more. after lifting the rotor axial free float increases and now it is 1.35mm now its 10 pm. tomorrow we will try to rotate the rotor.WILL THE ROTOR ROTATE?

Yeah maybe, but will it also tear up when you start it? Probably. Will the vibrations be very high when you start it? Yes for sure. Will you damage it on startup? Yes very likely. Will the turbine efficiency be very low if you get it operating? I think so.

Will you then have to overhaul it? Yes definitely. So why are you wasting time?

I advice you to contact the OEM (BBC) or any of the expert servicing team.

You have to balance the rotor. There is I feel no choice. Along with that you have to check the health/ residual life of the components.

Just shimming to get the clearance is not enough. What was the original axial float? the increase of 0.9 by adding just 0.1 alignment shim does not look healthy.

It needs a complete check up, starting with removing the rotor from the casing, and preferably under guidance.

Forcing a rotating machine to rotate when it does not want to is asking for trouble. Don't do it.

If you want to know if it is possible to rotate the turbine after what you did, the answer is : probably the rotor will rotate ( it must not touch the turbine static parts) but let us know what is your intention:

- do you want to rotate the turbine or

- do you want to launch the turboset and produce the electricity

If you want the turboset to return to service, making heat or power without break downs, please think of problems we have mentioned here. Let me focus your attention on some basic problems just now:

You have lifted the rotor 0.2 mm up, so the upper clearances within steam path are by 0.2 mm less. If it is impulse turbine probably it is not critical as the gaps are bigger than 0.2 :-) but at reactions turbine please assure yourself if the rotor does not touch the blade shround in upper casings. Please check the oil seals gaps at bearing pedestals. The next thing you have to take into consideration is the rotor's misalignment you have done. I mean turbine rotor and generator rotor. Such big lack of rotors concentricity is not allowed by OEM, I suspect

Let us know any news your turbine related,

what type of coupling is used? Before starting it will be necessary to check radial run-out of turbine at the coupling end. You have to take coupling apart, highly important!

use stetoscope to listen for internal noises when rotating.

It may potentially cost a life... if neglected.

good luck.

Contact the turbine manufacturer for advice, and possibly a service visit.

I do not think that it is a must to contact turbine manufacturer. The OEM's services are the most expensive one, usually. I would be enough to get support from company experienced in steam turbine overhaul. It can not be possible when turbine is under OEM warranty period but it is not the case

Does this story have the end? Did the turbine rotate or not?

Dear Guest,

Even though the Turbine is in a closed condition, and stopped for 5 years, the rusting and the oil sediments around bearings might have hardened.

You have to open carefully and clean and then box up.

DHAYANANDHAN.S