Product category:
Electrical systems
News Release from: ArcAd | Subject: Short circuit error tracking analysis
Edited by the Manufacturingtalk Editorial
Team on 16 January 2006
Tracking error in short circuit analysis
Online short circuit calculator carefully handles input data tolerances and tracks error propagation through massive computations associated with short circuit analyses.
Now, ArcAd tool performs more than otherwise tedious calculations assosiated with short circuit study We have implemented a parameter of tolerances to our service, which has an effect on final results within the analysis
This article was originally published on Manufacturingtalk on 14 Oct 2005 at 8.00am (UK)
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Many other procedures do not take into account room for error, which can distort final values.
If we were in a perfect world we would try to eliminate tolerances so that values can be precise without any assumptions.
Error in science and engineering does not mean a mistake.
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It rather means inevitable uncertainty that happens because of empirical measurements and cannot be perfectly corrected.
All measurements in practice and even in principle have some error associated with them; no measured quantity can be determined with infinite precision and zero deviation.
Without proper error analysis, no valid scientific conclusions can be drawn.
In fact, wrong results can happen if error analysis is ignored.
By including room for error we consider all tolerances both plus and minus.
Another factor to consider is reducing or extending values to their most significant digit.
This allows answers to be more accurate which reveals the hazard levels to be more precise.
In other words, the calculator validation procedure, input data analysis and algorithm for capacity calculations ensure that the results are not more precise than is justified by input data accuracy.
Typical commercial software have more interfaces and graphic content, which make them more appealing and expensive.
ArcAd's on-line tool is user friendly and is offered at a reasonable price.
It also comes accompanied with calculation examples showing the procedure in action.
ArcAd online short circuit calculator carefully handles input data tolerances and tracks error propagation through massive computations associated with short circuit analyses.
Listed are some rules for approximate calculations adopted by the calculator: 1 - When quantities are being added or subtracted, the number of decimal places (not significant digits) in the answer should be the same as the least number of decimal places in any of the numbers being added or subtracted.
2 - In calculations involving multiplication and division, the number of significant digits in an answer should equal the least number of significant digits in any one of the numbers being multiplied or divided.
3 - When finding the square root of a number, the result has the same accuracy as the number 4 - When doing multiple-step calculations, keep one more significant digit than required by rules above in intermediate results.
This digit is dropped off the final result.
In this manner, phenomenon known as 'round-off error' is effectively avoided.
5 - If one of the original factors has more significant digits than the other, round the more accurate number to one more significant digit than appears in the less accurate number.
The extra digit protects the answer from the effects of multiple rounding.
In conventional error propagation theory, errors always increase when quantities are added, subtracted, multiplied, divided or operated in any other fashion.
That is that the errors always combine in the worst possible way.
The calculator hard coded error propagation rules take into consideration the fact that the error in one variable happens to cancel out some of the error in the other variable and so, on the average, the total error will be less than the sum of the errors in its parts.
It can be proved that the results calculated using the rules above contain significant digits only.
We strongly believe that if resulting fault current margin error can not be quantified, then it is not engineering, but only a guess.
As far as we are aware, none of the available competing products performs proper error analysis.
It wouldn't be a problem if most accurate system equipment data were available.
Experience shows that by far most real world studies are built upon approximate and therefore more or less accurate input data.
The concept of precision is very important indeed and can impact results in surprising ways.
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