Bought a $300 thermal camera for finding heat in motor controllers and it actually paid off last week

I was working on a 15-year-old traction elevator with a random shutdown fault. The logs were useless, and everything tested fine with a meter. I pulled out this little Flir One camera I got for my phone, just on a hunch. Scanned the controller cabinet and one of the DC link capacitors on the drive was glowing bright yellow compared to the others. It wasn't failed yet, but it was cooking itself. Replaced it and the unit has been solid for five days now. I almost didn't buy the thing because it felt like a toy, but spotting that heat saved me probably a full day of chasing ghosts. Anyone else use thermal imaging for troubleshooting, or have a different trick for these intermittent drive issues?

2 comments

2 Comments

davidwright2d ago

Ever see a thermal camera catch something a data logger missed? My buddy had a weird pump drive that kept tripping on overload, but only after running for hours. All the currents and voltages looked perfect on the screen. He borrowed a thermal gun from another site and found one of the IGBT modules was running about 30 degrees hotter than its twin. The heatsink looked fine, but the thermal paste under it had gone bad. It wasn't shorted, just leaking heat like crazy under load. He re-pasted it as a test and the fault vanished. Makes you wonder what else we're missing without seeing the heat.

davidwright2d ago

That story about the thermal paste going bad is a great point. It reminds me of a time we had a cooling fan that passed its amp check but was barely moving any air. The motor was warm, but the real heat was in the bearing housing you couldn't even touch. The thermal camera showed the whole story the meter missed. Sometimes the problem isn't the part that fails, it's the part right next to it cooking from the extra work.