Big Clearance in Labyrinth

Did you clean and check the labyrinth for damage before replacing the shaft?

When you discussed it over the phone with the equipment manufacturer, what did they say?

they said there is contact between shaft and labyrinth. but we have replaced the shaft. and we used old labyrinth.

i just wondering if there is pretty big clearance in it. so it is not from that

Sounds like a rub between the shaft and bearing or labyrinth, like the manufacturer said. How long do you intend to run it like this? Are you planning to have the manufacturer's rep on-site when you overhaul it next time?

What did their representative say when s/he attended your site?

Did you check the shaft to Labyrinth clearance, looks like there is rubbing, is the labyrinth concentric to shaft i.e the radial clearance equal all around? Can't you try to machine a new labyrinth in workshop? what did you find when you first overhauled the turbine? why was it jammed?

WHAT BRAND STEAM TURBINE? HOW BIG? WHERE IS IT?

You could have been clearer in your presentation. The first thing you expressed, "shaft is jam"

Was that the new commissioning or the turbine was already on the run. If it was a sudden jam (seizure), for how long it was running satisfactorily?

The excess clearance at labyrinth should not heat up the shaft, but could lead to loss of power (due to internal bypass). If the subject turbine has balance piston and the excess clearance around balance piston labyrinths would disturb the proper thrust balancing. Besides loss of power, this would unduly load the thrust bearing and heat it up. Thrust is at the governor end, so possibly heating up the shaft and oil.

If your turbine is still running, stop and take action before it goes un-reparable by easy means.

If there was excessive clearance you should see signs of excessive steam leakage at the labyrinth. Instead you're seeing a "blue shaft", high bearing and return oil temperatures" and you're still running this turbine? Those are more likely signs of overheating in that bearing area due to bearing failure or metal to metal contact in that area. Sounds like a recipe for disaster. The next sound you could hear will be the screeching of retaining rings against casing followed by the whistling sound of flying rotor blades after they pass through the cracked housing.

ok, thanks all

we will overhaule it soon

Great, please share your findings, that should be a great contribution...

This is beyond me, but it sounds like you have a potential catastrophic failure. It's time to stop checking the internet and call in the people who commisioned it.

What is the worst case scenario ? Plan for it - things have a tendancy to happen when you least expect and at the worst possible time. No disrespect intended, but you need some advice on-site. You'll get good advice here, but can you be certain ? Bight the bullet and accept that it's one of those things when you need eyes-on help.

CR4 has some real experts, but you need to verify.

sure. i will do what manufacture said