Message Board Thread - "Related between ampere VS build up of heat."

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Related between ampere VS build up of heat. 20732 3/20/2007
Some of thermal load at the blower of steam generator get hot. its about 240 F and more. how to determind that condition is not good..?. the normal condition is 170 F.and how related ammpere with heat built...
 
Re:Related between ampere VS build up of heat. js black 8/16/2007
20732 wrote:
thermal load at the blower of steam generator get hot. its about 240 F and more. how to determind that condition is not good..?. the normal condition is 170 F.and how related ammpere with heat built...
Hi am quite new in thermography but i dont think there is a baseline data that relates current to build up of heart or radiation intensity BUT yes the higher the loading the greater the intensity but this is relative to what is being thermographed,its geometry, surface structure,reflected apparent temperatures and even the emissivity of the material. i hope ihave assisted you in some way because am only 1 week into thermography in the electrical field,if am wrong i'll accept the critism positively and because am also learning.
 
Re:Related between ampere VS build up of heat. Bob Berry 8/16/2007
ITC provides a customer utility CD to all students attending their courses. On this CD there is a load correction excel application.

Its is pretty good.
 
Re:Related between ampere VS build up of heat. Toolman 8/16/2007
Bob is right on the money, the resource CD has some great tools on it.

With respect to the original question I'm going to jump right out on a limb and assume you're talking about an electrical connection. The amount of heat generated is a function of the dissipated power. If you refer back to ohm's law, power is equal to the square of the current times the resistance (we'll ignore PF). What this means is that if you double the current, the amount of power dissipated increases by a factor of 4, triple it & the factor is 9, etc.

For example assuming r = 1 ohm:
Current(I) Power(W)
5 25
10 100
15 225
20 400

How this relates to the actual temperature is more complex & takes into account a bunch of other factors, but there is definitely a relationship.
 
Re:Related between ampere VS build up of heat. Laland 8/21/2007
Hi Bob,

I attended a Level 1 ITC course in 2004 in the Philippines, but I dont remember that we were given any utility CD. How can we obtain that CD?
 
Re:Related between ampere VS build up of heat. jimmyc 10/16/2007
20732 wrote:
thermal load at the blower of steam generator get hot. its about 240 F and more. how to determind that condition is not good..?. the normal condition is 170 F.and how related ammpere with heat built...
I am also new to the thermography field. However, I have been interested in this question for some time. while the resource CD is a good tool, I am not sure exactly how the temperatures are calculated.
Also I have considered the Ohm's law approach. this approach seems to be somewhat accurate under certain circumstances. The main disadvantage is calculating the heat losses. As a general rule it is usually considered to be about 1/3 rd of the power is lost. So while calculating the resistive power and subtracting 1/3rd of that power is fairly accurate. It cannot be truthfully relied on. The temperature curve seems to change as the temperature increases. Also I have attempted to apply a parabolic function to this problem. this does not seem to be accurate at all. Lastly, I have attempted to determine both heat load and losses by using the point slope method. In this method one lists the temperature and the corresponding current measurement as a Paired coordinate. An example would be 36 degrees C @
10 amps would correspond to (10,36). At this point one calcualtes the slope of the line. Hpefully this would modelthe heat generation along with the heat losses. Unfortunately, I have only been able to make general predictions of the final temperature achieved. While these calculations can give one some idea of what the conditions are, they are a very inexact measurement.
 
Re:Related between ampere VS build up of heat. Lisa West 10/29/2007
Laland wrote:


I attended a Level 1 ITC course in 2004 in the Philippines, but I dont remember that we were given any utility CD. How can we obtain that CD?
Dear "Laland,"

If you email your certification number to "itc@flir.se" along with a request for the utility CD, we'll send one to you.

Lisa West
ITC
 


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