It’s no secret that infrared can be used to diagnose problems with electric motors in industry, but residential applications? As ITC Instructor Ron Lucier recently discovered, possibilities exist at home as well, this one involving his pool pump motor:
Returning from a recent Level III class in Nashua I heard an awful noise in my backyard when I stepped out of my car. Pretty quickly I determined it was my pool pump motor (1 horsepower). What a racket. Sounded like just a bearing so I brought out my trusty vibration acceleration detector: a screwdriver. Measuring at each bearing of the motor and the pump I didn’t feel very much. However, I noticed a black spot on the side of the gold painted motor. It was time to get out the IR camera: my brand new FLIR T650sc.
I would find out the next day that the long wave emissivity for this paint is 0.91 so making the correction the hot spot was about 201 F! Good thing that I didn’t try to touch it!
The next day I’m almost $300 poorer, but I have a brand new motor with seals and gaskets too. No instructions but I’m a Mechanical Engineer! I can figure this out!
I like science and I’m always looking for data for my Research & Science classes so I keep an A6703sc mid-wave camera with me. Nice camera – 640 by 512 pixels and very flexible for basic research. The camera is operated via a PC so I set up to take one last data set for this motor. My recording conditions were one image per second for a couple 10 minute periods.
One very interesting finding – the motor emissivity turned out to be 0.64 in the mid-wave and 0.91 in the long-wave. So much for emissivity tables!
Here is a screen shot from ResearchIR 4 near the end of the motor run:
The motor hadn’t gotten up to its maximum temperature yet after 25 minutes of running and it was making even more noise so I terminated my test before I let the smoke out of the wires.
This was after 30 minutes of total run time. A common question we get asked is “how long does it take to get things warmed up before we should inspect them?” Our standard answer has always been at least an hour. This seems to validate that.
The old motor was allowed to cool. I found a place to cool myself (boy I like FLIR Tools+ Panorama!!!) The thermal image of the pool is made from nine T650sc pictures by the way:
Now to the motor replacement. The motor came with general instructions, pretty easy. The mechanical seal didn’t. No instructions on how to remove the pump from the motor. YouTube turned out to be the answer and the job was fairly easy, minus the mosquitos of course. Total time about 1 hour, including tool finding time.
The bottom line here is that we all know how handy IR thermography can be in our daily professional and work lives, but it has a role at home too. I’m fortunate to have many tools at my disposal and an aversion to paying somebody for something I should be able to do myself.
Our pool season in Central Massachusetts is pretty short – generally from Mid-May to the end of August – so we have to make the best use of our warm weather time!
- Ronald Lucier, ITC Instructor, ASNT NDT Level III TIR
