GE Frame 6 wheelspace temperature difference

P

Thread Starter

Patrick

Did a search here on wheelspace thermocouple temperature issues and had some fine reading but, didn't find anything that addressed our current situation.

We just came out of a major and this is what I walked in on today (we weren't suppose to start until 06/29).
TTWS2AO1.....884 deg.F
TTWS2AO2....1233 deg.F
TTWS3FO1.....822 deg.F
TTWS3FO2.....962 deg.F

Some folk's above me think it's an instrument issue. I don't. Any ideas? Thanks for a great resource for information (this website forum). Patrick Conner
 
Patrick,

I have seen a similar situation. One shorted input to the thermocouple card can bring down four or five other inputs. One would tend to believe this could never be so, but I have had a chance to examine this closely, and it does happen.
 
Kindly check the milli volt of the thermocouples at field and system end. Many occasions our thermocouples are get damaged after it was installed due to other mechanical maintenance activities.
 
c^2,

Have you seen this on Speedtronic turbine control systems? If so, can you be more specific about which version of Speedtronic and which cards in that version of Speedtronic?
 
The searches you have done should have indicated the most common cause of the indications you showed are the result of poor re-insertion of the T/Cs into the wheelspaces. It's physically impossible for there to be such a high differential between two T/Cs measuring the temperature in the same wheelspace. So, one or both T/Cs were likely re-inserted after the outage improperly.
 
As c^2 told, we had a same situation like that. 3 of our vibration was very high. The problem was shorted connection. when the shorted was repaired, all fixed.
 
Mxromen,

What kind of vibration sensor?

What version of Speedtronic? Which terminal boards were the vibration sensors connected to?

Were IS barriers/zener diodes used in the circuits?

As for "shorted" T/C inputs, you can place a copper wire jumper between the two T/C input terminals on any Speedtronic control panel and all that will happen will be that the ambient temperature where the jumper is placed will show for that input. There will be adverse affect on any other T/C reading.

Now, if your definition of "short" is different from a direct connection between the two terminals of a T/C input, then it's possible that something else could occur. If you meant a ground, most digital Speedtronic turbine control panels can use either grounded or ungrounded T/Cs in any combination without any problems. If you meant a "stray" voltage or current being connected to one or both of the T/C input terminals, that would not be a true definition of a short.

So, let's be careful how we use our words here. And be specific about what we're talking about.

Please provide details not just anecdotal information.
 
I apologize for the late.....THANK YOU to all who replied.....I went on vacation for 2 weeks, work a rotating operator schedule and was lead on an NH3 TK T/A. Man, time is blowing by this year!

Our problem was determined to be two improperly installed probes. Our Instrument Techs figured it out and plan to repair when convenient.

I've learned a little bit more about these machines and suppose will continue to do so until retirement.

Again, thank you, Patrick.
 
Top