Message Board Thread - "emissivity of materials"

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emissivity of materials NikoSojo 3/10/2009
hello, thermographers. I have some questions (plese do not copy/past from emissivity table)
1. value of emissivity for aluminium electrical busbar, 20kV voltage, non-insulated, busbar connected to circuit breaker, heating in connection
2. value of emissivity for copper electrical busbar



Thx.
 
Re:emissivity of materials jvoitl 3/10/2009
If you want a more accurate emissivity than what is in the tables you'll have to measure it. I realize this will be difficult on a 20 KV bus and you will have to get a power outage to do it. The true emissivity will vary with the amount of corrosion, dust, or other variables.
 
Re:emissivity of materials NikoSojo 3/10/2009
ok, if i use a data from ThermaCAM Reporter Manual E-table, E for heavily weathered aluminium is about 0.94. I supose, aluminium busbars are havely weathered material, and this E-value can be used in my report for inspected substation.
Is it?
 
Re:emissivity of materials manuel-thermoimagen 3/10/2009
Yes,, my personal opinion which can be wrong, is that you will have to show your camera's inspection parameters when walking around taken and saving images (ambient Temp, humidity %, distance, Temp reflex) etc.

i guess this several inspection values often are used for future nexts inspections in order to obtain the most similar inspection conditions, so, when new thermographer or company arrives, can setup their cameras ;)

 
Re:emissivity of materials NikoSojo 3/11/2009
thx, manuel-thermoimagen

also I have a very basic question, what is reflected temperature and how it could influence the result of termography.

And one pic
possibly, what T of inspected object could be about 132C - it is 0.4kV aluminium busbar
 
Re:emissivity of materials Bob Berry 3/11/2009
NikoSojo wrote:
nuel-thermoimagen

also I have a very basic question, what is reflected temperature and how it could influence the result of termography.

And one pic
possibly, what T of inspected object could be about 132C - it is 0.4kV aluminium busbar
Emissivity and reflected temperature will have a very big influence on the measured temperature. you need to have these set to the correct value. I do not recommend you use table values if you require any degree of accuracy. These concepts are explained during Level 1 training. If you have not already attended a level 1, then you should get yourself along to a course.
 


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