How Hot Is Too Hot When Shinny Metals Lie

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IR Talk


A couple of weeks ago I was at a power generation plant performing a critical commissioning inspection of two brand new turbines that put out 230 MW at base load. Upon scanning the PDC’s and PEECC’s of their MCC buckets and panels I come across a shinny bolt that was screaming “Hello I’m Hot”. For those of us that know how emissivity works we know that a shinny bolt only wants to tell the camera 10% of the truth and 90% a lie. So how do we know how hot that shinny bolt is when it is showing hot? How do we get the actual temperature, the answer is you cannot. Using your Level 1 & 2 training can help you make some assumptions but knowing that they are just assumptions.  So when I came across this bolt screaming at me I knew this was a very serious situation that need my attention ASAP. I grabbed a couple of pictures with my IR camera and phone for documentation and then told the electrician to close the bucket very carefully and to get ahold of operations. The electrician did exactly that. This MCC bucket was the starter for one of the water pumps for the fin fans that cool the water down. If you have worked at power plants, you might know that most of them have a redundant system just for issues like the one we came upon. The electrician worked with operations to immediately swap from this pump to the other standby pump so this one could be shutdown ASAP. So, the question becomes well how hot was that bolt? Above is the Infrared picture that I captured just when the bucket was opened. 

The measured temperature of the shiny bolt with a low emissivity was 551F. The first thing in my head was ok if my camera is telling me the bolt is 551F the true temperature is at least double that if not more. Looking at the picture of the top side of the contactor that I took with my phone told me I was on the right track with my thought process as you can see the metal is starting to take a different shape from the B and C phases. The connection is so hot it was literally starting to melt the metal and you could smell that distinct smell of burnt electrical wire and components.  

Brand new turbines that put out 230 MW at base load.

I always get the comments from the customer “I don’t know what you are going to find because it’s brand new”. My response to that is “just because it’s new doesn’t mean it was put together right”. Human hands put all of this together and things happen. I’m not saying the craftsmanship is poor, I’m just saying things happen. It’s important to make sure new projects are looked over by third parties, if I had not been there for the commissioning of this project this would have been a catastrophic failure that could have had far reaching consequences. Working with our customers on projects whether they are brand new or working on their equipment that has been in place for years you can always count on The Snell Group because “Our Knowledge. Your Advantage®”.

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