Brak tytuu - Now consider a large box circuit breaker where

Brak tytuu

14 wrzesie 2017 - Now consider a large box circuit breaker where

Not to belabor the point, but even if you are looking directly at the hot contact, what is its conductivity and emissivity at the specific temperature as it heats up? If you have direct sight of an overheated copper contactor, Ohm's Law is likely all you need to consider if not, then you need to think about these other factors. You also need to know the specific heat of the components and the path the heat travels to reach the IR Radiometer, the IR Camera.

Basic math tells you if the system is running at 25% then the heat from a problem will be about one sixteenth the heat when run at full power. Heat travels in three dimensions, some of that travels through the grease surrounding the bearing, some conducts through metal, much of it goes elsewhere. I explained to the Chief Engineer why this was classed, not as the software wanted to classify it, rather as a high priority repair, but why? People seem to think the level of power running through a circuit is unimportant in thermographic analysis as if the camera had some mysterious power? However, the same people are familiar enough with Ohm's Law to remember that P=I(IxR), or the power is equal to the generator bearing current squared times the resistance and ought to conclude that if the power is at 50% the heat generated from a problem is four times that if the same system at 25% and 1/4 that if it were at full power..e. I recommend using ISO assessment criteria, and the difference between, say, a connector under 25% load at an 8C rise in temperature (an ISO "Advisory" issue) to running the equipment at full power according to Ohm moves this assessment to a problem requiring immediate attention. Double the power again, four more times the heat. problems) to Tilting pad journal bearing generate heat and that heat to build, then conduct, convect and emit to the imaging device so the thermographer can see the issue at hand and correctly analyze the equipment.The seaman asked if we needed power to equipment we inspected. Without this, you cannot achieve a correct reading or analysis. This allows for improper resistance (i. Most thermographers insist there be at least 50% power for five minutes before an inspection. Look at the casing of a motor with an overheated bearing and imagine how far the heat has traveled and though what to reach the camera. I have needed to inspect very important equipment which could not be fully powered, at lease while I was present, and seen a small rise in temperature.

Now consider a large box circuit breaker where the hot contact radiates heat at a specific emittance into an air pocket, some energy heats the air inside, and some energy is absorbed by the Bakelite casing, conducted to its surface and then emitted again, quite the convoluted path. Others have asked how much power we need to analyze equipment


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