safe thermography

[jimmy2times]

We have a task to conduct thermography on high power switchboard on ship with limited rear access (500mm) between back of switchboard and bulkhead. One option is to put on thermal survey windows but this will be costly exercise.

One though I had was to de-energise the switchboard (we have redundancy in another switchboard, so no loss of plant), remove the rear covers ready for thermography and then re-energise switchboard. Run for about an hour. Then shutdown and in that time then a couple of thermographers gets around the rear and quickly surveys the rear sections with the board dead. i.e. thought being any latent heat in hotspots would still be detectable. Obviously not as good as an energised board.

Otherwise thinking on camera mounting on stick and use of remote control via pc with switchboard live.

We have ship's motions to consider which makes the risks slightly higher than you have on landbased installation.

Thoughts appreciated.

 

[Zogzog]

Windows are not very expensive at all, you are going to have to do the surveys many times in the future so they pay for themselves rather quickly.

 

[alehman]

At least one manufacturer in the U.S. produces windows that can be angled and can rotate to allow better view of the interior. Might help for restricted space as you mention.

Alan
The engineer's first problem in any design situation is to discover what the problem really is. Unk.

 

[SparkyAt10]

You can always ducter test with the boards offline, checking the micro-ohm impedance across connections. It is more work than a Thermographic survey, but safer.

The advantage to me of Thermographic surveys is that when you don't know where to look for a problem, it can jump out. When you ducter test, you need to understand where every connection is.

I can also think of a few things we never would have found with just ducter testing-- bad seating of circuit breaker trip units, failing current transformers, etc. they tend to fall in the <1% category of issues found in my experience though.

Windows never seem to work properly. You could always try a remote controlled system, but it doesn't seem worthwhile. Ducter plus thermo for what is easily accessible and loaded seems best to me in your case.

 

[racookpe1978]

The MILSPEC (shock and electrical and fire, etc, etc, etc) testing for permanent installation of the windows could never be affordable.

How heavy are the sensors (the thermal camera)?

Do what you described, but have the camera mounted on a handle or rail (or more expensive and troublesome) a pair of angle iron rails mounted to the wall opposite the switchboards. Then take the photo's without needing a person to crawl back behind the cables and boards. If they could be hand-held on the bar, you could do a area survey to look at hot spot, but movement of the guy's hands and arms would make it a bit blurry for really detailed work.

 

[caporter]

I would question how effective turning off the switchboard would be with the power off. The current through the components is what causes the temperature differential. Once de-energized the component start cooling off skewing the results. Best bet is put in the IR windows.