I mean, all that thermal imaging is really doing is checking for hot spots. Just follow NFPA70B to find when you should be performing PMs on this transformer. But really the thermal imaging would tell you to tighten some bolts. Why not just clean the contacts and tighten the bolts? That’s a shit consultant - recommending people try to kill them self to see if a bolt is loose is dumb. Turn the thing off and tighten the bolt.
An IR window won’t tell you if the windings are going bad, and that’s much more critical than the terminations. With the transformer de-energized, do a winding ratio test at the frequency recommended by NFPA70B, while you’re tightening bolts.
The fucked up part is that maintenance consultant probably gets pedigree by commenting on the NFPA concensus review sessions to advocate for his way. Feel free to PM me if you need help getting that fucker walked off site. I love throwing the code book at people that try to kill maintenance workers.
It was a hypothetical situation, don’t worry. Not really outside of the realm of things I’ve seen 🫠
I think it depends a lot on how critical the system is and what the risk of failure is. I work in critical infrastructure and we aren’t going to rely on a code minimum PM schedule. We don’t want to run our transformers to failure, even if we have redundancy, because lead times are fucking crazy right now. Like, more than a year. You are limited in terms of shelf spares due to space and storage/exercise requirements.
I’m not an electrical person but our electrical maintenance department seems to be on board with condition based maintenance so there must be some benefit to them. We do require IR windows and other features on equipment that allow the tests to be done safely. Apparently the IR windows are easy to retrofit.
The other benefit is tracking trends over time. Some of the offline analysis (like the winding ratio) you mentioned will give you data, but you can check more things and more frequently with the windows. You can see when a particular bus connection is slightly warmer than the others, for example, and decide to take it down sooner than required to have a look and correct.
It’s a different situation than what we are describing but we recently had a motor failure and one of the three phases was getting slowly hotter over time (we had online trends) until it shorted and kablamo! No one was monitoring those temps but we sure are now lol.
That makes sense. I shouldn’t have bashed IR windows. The plants that mandate rigid conduit everywhere, IR windows make sense and are good. For the limited budget plants, I think IR windows on transformers are low priority. But infinite budget, IR windows are great.
IR windows have a lot more use cases outside of transformers where I think they are more important. And everything has to do with frequency and down time availability.
The last job I worked was a steel mill. I was in charge of all electrical distribution from utility to disconnect prior to production equipment. Because of the metal dust, we needed to vacuum out distribution equipment yearly at a minimum and NFPA70B recommended some tasks yearly for us. I left when my 2 day outage on a 3 day weekend was canceled. I consolidated the outage plan to a single day, and they still wouldn’t let me have it. Once we got a year behind, I left. I’ve been gone a year, and they still haven’t done it.
I had the main transformers on a 5 year EOL plan because of oil samples and age. The lead time was 18 months for each, and they needed 3, lol. The EOL plan was also neglected.
I would’ve felt more comfy with IR windows lmao but I wasn’t going to stick around to be the scape goat when the plant goes down.
I mean, all that thermal imaging is really doing is checking for hot spots. Just follow NFPA70B to find when you should be performing PMs on this transformer. But really the thermal imaging would tell you to tighten some bolts. Why not just clean the contacts and tighten the bolts? That’s a shit consultant - recommending people try to kill them self to see if a bolt is loose is dumb. Turn the thing off and tighten the bolt.
An IR window won’t tell you if the windings are going bad, and that’s much more critical than the terminations. With the transformer de-energized, do a winding ratio test at the frequency recommended by NFPA70B, while you’re tightening bolts.
The fucked up part is that maintenance consultant probably gets pedigree by commenting on the NFPA concensus review sessions to advocate for his way. Feel free to PM me if you need help getting that fucker walked off site. I love throwing the code book at people that try to kill maintenance workers.
It was a hypothetical situation, don’t worry. Not really outside of the realm of things I’ve seen 🫠
I think it depends a lot on how critical the system is and what the risk of failure is. I work in critical infrastructure and we aren’t going to rely on a code minimum PM schedule. We don’t want to run our transformers to failure, even if we have redundancy, because lead times are fucking crazy right now. Like, more than a year. You are limited in terms of shelf spares due to space and storage/exercise requirements.
I’m not an electrical person but our electrical maintenance department seems to be on board with condition based maintenance so there must be some benefit to them. We do require IR windows and other features on equipment that allow the tests to be done safely. Apparently the IR windows are easy to retrofit.
The other benefit is tracking trends over time. Some of the offline analysis (like the winding ratio) you mentioned will give you data, but you can check more things and more frequently with the windows. You can see when a particular bus connection is slightly warmer than the others, for example, and decide to take it down sooner than required to have a look and correct.
It’s a different situation than what we are describing but we recently had a motor failure and one of the three phases was getting slowly hotter over time (we had online trends) until it shorted and kablamo! No one was monitoring those temps but we sure are now lol.
That makes sense. I shouldn’t have bashed IR windows. The plants that mandate rigid conduit everywhere, IR windows make sense and are good. For the limited budget plants, I think IR windows on transformers are low priority. But infinite budget, IR windows are great.
IR windows have a lot more use cases outside of transformers where I think they are more important. And everything has to do with frequency and down time availability.
The last job I worked was a steel mill. I was in charge of all electrical distribution from utility to disconnect prior to production equipment. Because of the metal dust, we needed to vacuum out distribution equipment yearly at a minimum and NFPA70B recommended some tasks yearly for us. I left when my 2 day outage on a 3 day weekend was canceled. I consolidated the outage plan to a single day, and they still wouldn’t let me have it. Once we got a year behind, I left. I’ve been gone a year, and they still haven’t done it.
I had the main transformers on a 5 year EOL plan because of oil samples and age. The lead time was 18 months for each, and they needed 3, lol. The EOL plan was also neglected.
I would’ve felt more comfy with IR windows lmao but I wasn’t going to stick around to be the scape goat when the plant goes down.
I worked in chemical manufacturing before infrastructure and there is no way in hell I’m going back to anything that isn’t strictly regulated lol.
Not that we don’t get our fair share of nonsense, but manufacturing is a whole other world of crazy.
Ha I feel that. Manufacturing is fun as fuck but kinda ridiculous and sometimes stupid dangerous