kind of lazy to explore . very new to this IR. we are thinking of introducing IR in our rotating equipment cbm activity. any article or something similar explaining on the applicable scope?

thanks.

In order of priority (imo):
- Look at bearing housings for sign of hot bearing. If see unusual difference, investigate (although note that greased bearings may be hotter than sisters simply because they were just greased).
- If accessible, look at coupling.
- Look at motor temperature (for example center of stator). Does it suggest the winding may be unusually hot? If so investigate further.
- Look for any unusual patterns/differences that get your interest and investigate.

thanks pete. that is enough for me to start the engine to roll.

Also,

if coupling is not accessible (most are covered...), can an IR mirror be placed safely underneath to allow a reflective view?

Good idea. They are also called "first surface" mirrors. When I shopped, they were expensive at places like Edmund's scientific, but dirt cheap at other places. We got one around 12" x 18" from Delphi Glass for around $25. Works fine for relative images. Just a little cumbersome and fragile to carry around. If I were to buy another I would get a smaller one.

quote:

Good idea. They are also called "first surface" mirrors. When I shopped, they were expensive at places like Edmund's scientific, but dirt cheap at other places. We got one around 12" x 18" from Delphi Glass for around $25. Works fine for relative images. Just a little cumbersome and fragile to carry around. If I were to buy another I would get a smaller one.

1/8" flat aluminum plate works as well as a front-surfaced mirror; doesn't really need to even be polished. If it gets too banged up , recycle it and get a new one. I only use front-surfaced mirrors for critical measurement applications.

quote:

Originally posted by John Snell:

1/8" flat aluminum plate works as well as a front-surfaced mirror; doesn't really need to even be polished.

John,

What would be the emmisivity setting for aluminum mirror case?

David

What is really needed is the REFLECTIVITY (1-emissivity) value; for aluminum this is often 90% or greater.

But it is more complex that just reflection! Because the aluminum is not a perfect reflector, it too will be emitting radiation and, thus, we need to correct of it's temperature.

One then must input a correction for the emissivity value of the surface being reflected in the thermal mirror to arrive at a fully corrected radiometric temperature.

Most camera or analysis software does not have the capability to make these corrections though, in some, you may be able to use the correction factor reserved for transmission and temperature of the transmission media.

It is probably easiest (and maybe just as accurate!), even if not proper, to simply assume 100% reflection and enter an emissivity correction based on the surface being viewed in the mirror.

If a higher degree of accuracy is required, a front-surfaced mirror (with virtually perfect reflectivity) or some practical testing with the aluminum plate and the temperature ranges being viewed would be in order.

Sorry if this is confusing, but imaging looking in a visual mirror. It matters if it is clear or fogged up and in either case we are not looking at reality but a reflection of reality which we must decipher to one degree or another.

With infrared, getting in the "thermal ballpark" is not hard but being more accurate requires a great deal of careful technique, precise skill and, honestly, persistence.

I have had pretty good luck with a shade 12 welding glass. The stuff that is used as a replacement lense for serious welding masks. They are fairly cheap and quite durable.

My readings from the welding glass are always within a 0.5C when I have done a comparison to a direct reading. I am sure some of the error is even my awkward attempt at holding the mirror steady while focusing. Okay okay it was not the best lab test.

Regards,

DanS