One of the flames is continously failing. When sensor wires are removed, power supply is measured to be 330 vdc, & with sensor connected it's showing o v dc. We have GE Frame 6 machine with Mark V controls. Detector is Honeywell make. What could be the possible reason?

Another diagnostic alarm appears as TCE1 Flame out of limits for the sensor. How to rectify, please?

Thanks a lot in advance.

 

I'm not an expert, but I'd say it was shorted.

Regards

cww

 

When you say "...continuously failing..." what exactly do you mean? Is the output/feedback excessively high, or zero? Is this happening only when the turbine is running, or even when it's shut down (i.e., no flame exists in the combustors)? When troubleshooting and asking for assistance, one should provide as much information as possible to receive the most timely and concise response possible.

Another factor affecting flame detectors' ability to sense flame is the cleanliness of the lens. Have you checked/cleaned the lens? (Refer to the Honeywell instruction sheets for information on acceptable cleaning solutions/methods.)

This author's understanding of Geiger-Mueller flame detectors (the type which Honeywell makes and are used on GE-design heavy-duty gas turbines) is that when they detect flame they temporarily short, and the frequency of shorting is proportional to the intensity of the flame. If the output is continually shorted, especially when there's no flame, there's a problem.

The intensity of flame detector output/feedback can usually be seen on a display on the <I> or GE Mark V HMI; the names of the CDB (Control Signal Database) signals driving the bargraphs on the display are usually FD_INTENS_n, where "n" is 1 through 8, depending on which flame detector input you are observing.

But Curt Wuollet is probably correct--the flame detector is probably failed (shorted) and should be replaced. BE AWARE: Honeywell flame detectors are POLARITY SENSITIVE!!! If you hook up the detector with the wrong polarity, it won't be immediately damaged, but will be very shortly after flame is sensed by the detector. Irreparably damaged.

The 'out of limits' alarm means that the detector output is not what it's expected to be for the given operating conditions (another indication that it's failed or failing and probably needs to be replaced).

Feedback is one of the most important aspects of being a part of any forum community like control.com. When one posts a request for information or help, if one receives a helpful or informative response--or even if the information provided was a complete miss and totally inappropriate--the originator is obliged to provide feedback to let others who read the thread know if the help or information was useful in resolving the problem or answering the question. Lots of people read these exchanges, and many have similar problems or questions. Further, many use the very powerful search feature of control.com to look for possible previous postings related to their issue--and feedback lets them know if the information provided was helpful, or not. It's also helpful for respondents to know if they were on the mark, close to it, or completely off the mark. Everyone learns in a forum like control.com, those who ask questions or those who provide responses.

You have opened several threads and have provided little or no feedback. The point of having an open, public forum such as this is to share information--including feedback--with as many people as possible. (And, for this author, to keep from answering the same questions over and over and over and over again....) This is a community, and when we all contribute--including those who ask for help or information, in the form of feedback--we all gain.

markvguy

 

Sounds like you need a new sensor. 330Vdc indicates that you have an ionization tube sensor which have life measured in years. Most become contaminated and lose sensitivity over time, but a sometimes they short out.

The flame out of limit alarm makes sense if this is the case, because normal operation is that that tube looks open when no UV radiation hits it, and "conducts" in small pulses of current when gas is ionized by UV. Full short would put the current out of range highh. The alarm should go away when you replace the sensor.

 

why not replace the presumed failed sensor with other sensor which work with good condition or exchange the wires position at PTBA terminal board?

 

TO MARK V GUY,

I am Really thankful to you in providing your valuable suggestions to my questions which are being posted by me in this open forum.

Basically the situation is like also half done in every case as we are not getting the possible outage as generation is main aim of our organisation.

But in case of flame detector: before start UP of the machine, we already swapped the flame detector wiring at PTBA Card & still under observation to find out any channel fault occurs. As no outage is available further checks couldn't be done.

That's the reason why may be the certain feedback would not have been updated in this forum specially as replied by you.

Certain comments/suggestions could not also be applied as there is no possible outage in that particular machine.

Certainly I will post to you all neccessary feedback once we carry out certain action.

Please advise & cooperate with valuable suggestions.