Power factor and VA vs Watts

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ggunn said:
This gets into the realm of the philosophical, IMO. Are instantaneous values of impedance important in an AC environment, anyway, and/or do they even have any real meaning? :)
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I think that for practical purposes, for everyday calculations their impact is negligible. In the same manner as we ignore all the numbers after 2 decimals in Pie.

However the further we get away from pure sinewaves, the more POTENTIAL real impact will they have. Not just yet, I think. We haven't even touched on the variable resonant crossovers that will throw all this into another loop.
 
weressl said:
I think that for practical purposes, for everyday calculations their impact is negligible. In the same manner as we ignore all the numbers after 2 decimals in Pie.
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The only number I associate with Pie is "four and twenty". :grin:
 
Smart $ said:
Yes, I disagree... in a sense.

Proof is in empirical evidence.

Calculations are just a means to determine values when empirical evidence is not available.

If the calculations don't match the empirical evidence, what good are the calculations?

Granted we have a fair or better understanding of electrical phenomenon, and calculations to match, but someone first had to compare the calculation results to empirical evidence so as to affirm the validity.
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From Wiki:

"It is important to understand that the outcome of empirical research using statistical hypothesis testing is never proof. It can only support a hypothesis, reject it, or do neither. These methods yield only probabilities."
 
weressl said:
Empirical evidence is no proof that an exception does not exist. Does not matter how many times you repeat the same test with the results you would have no proof that an exception does not exist.

Calculations ARE proof that an empirical evidence holds up as as an absolute truth.

Your argument only proves the same. If the empirical evidence does not match the calculations then the base of the empirical evidence is unsound. In otehr words your evidence may appear to be empirical in quantity but has a qualitive failure in some of its assumptions and theories.

Empirical evidence is only accepted in soft sciences, such as medicine where the variables are just so great that even with supercomputing capability we are unable to assemble the right formulas.
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weressl said:
From Wiki:

"It is important to understand that the outcome of empirical research using statistical hypothesis testing is never proof. It can only support a hypothesis, reject it, or do neither. These methods yield only probabilities."
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It appears my terminolgy has sent you down the wrong path. Sorry about that, but the term "empirical evidence" is what I recall learning in school. Perhaps I wasn't paying attention. Nevertheless, it appears the current proper terminology is "empirical data".

Regardless, the gist of my statement stands, no matter how you want to perceive it. Prior to the work of Faraday, Kirchoff, and several other notable electrical figureheads through history, formulas and calculations therewith have changed over the years, but the phenomenon and the empirical data have not.

If there be an exception to data versus calculated values, then you have the wrong formula, or didn't accurately take all parameters into account. How many times in the implementation of electrical work do we say the calculation is adequate rather than precise, for the result may vary from actual. Which is correct, the actual data or the calculated result? I seem to recall it wasn't too long ago that the IEEE changed the formula for calculating voltage drop, because the former calculation had a known error.

Seems to me like you want to make this a chicken or the egg discussion?
 
The thread has changed to "Models of physical phenomena are a poor second to emperical data" Okay.

Warning: Philosophy discussion to follow - Escape while you can.

Smart $ said:
... Prior to the work of Faraday, Kirchoff, and several other notable electrical figureheads through history, formulas and calculations therewith have changed over the years, but the phenomenon and the empirical data have not. ...
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Every one of these guys developed a model of the physical phenomena and then did research to prove or disprove it.

Did the physical phenomena change? No, but the understanding of it did. We can't see any of the attributes we are trying to understand or measure. The best we can do is to measure the effects and make calculations to arrive at a parameter value.

Volts: You can't see the electric field or point to the direction of the force vector. But we can connect a coil to the voltage source, which will drive a current through the coil, which makes a magnetic field that moves a meter needle coil against a spring.

Current: You can't count the electrons, so we use the same meter, with fatter wire, and measure the same magnetic field pushing on a meter needle coil.

How about resistance? You can't even measure it at all. The best you can to is to pass a current through it and measure the voltage. The resistance is defined as V/I. Whoops that is a math model. Now what?

So, did the emperical data change? Oh yeah. As we learned about the physical phenomena and the effects, we developed better measurement techniques. And that changed the data.

(Quote attributed to Einstein: If the facts don't fit the theory, change the facts.):roll:

Smart $ said:
... Which is correct, the actual data or the calculated result? ...
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Most times the calculated result. Here is an example: We have a 2500kva transformer. Calculated short circuit current is 60KA. We are going to buy 65KAIC breakers for the first switchboard. Do you really want to throw a bolted fault on the transformer and measure the SCC? Or do you want to believe the calculation from the model?

How about the breakers. Do you want to test them at 60KA? I hope not. They are probably not rated to open more than once or twice at rated fault current. I say believe the calculation from the model.

Smart $ said:
... I seem to recall it wasn't too long ago that the IEEE changed the formula for calculating voltage drop, because the former calculation had a known error. ...
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Okay, that's good. The IEEE learned a bit more about physics and changed the model parameters. Tell me, in the past have you just made a VD calc and believed the wire size it said you needed? Or did you install the wire, load it up and then go out and measure the VD? I've only measured one - issue with the AHJ and a firepump.

Smart $ said:
... Seems to me like you want to make this a chicken or the egg discussion?
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Hummmm .... I've always thought the egg had to mutate (or evolve). Understanding of the physics was not created.

Someone came up with a model (a theory). And then did the testing to show that the model was true more often than not, and also to test and understand the limits of applicability.

You made a comment about calculations not being accurate. That's true. All models of physical phenomena have assumptions and limits of applicability that affect the accuracy of the calculation. Then when one adds in the measurement error, measurement technique error, pure technical screwup, instrument error, instrument algorythm error, ain't nothing exact. Anything man made has a tolerance - even your emperical data.

So ends the philosophy of mathematic models according to cf
 
Cold Fusion said:
The thread has changed to "Models of physical phenomena are a poor second to emperical data" Okay.

Warning: Philosophy discussion to follow - Escape while you can.


Every one of these guys developed a model of the physical phenomena and then did research to prove or disprove it.

Did the physical phenomena change? No, but the understanding of it did. We can't see any of the attributes we are trying to understand or measure. The best we can do is to measure the effects and make calculations to arrive at a parameter value.

Volts: You can't see the electric field or point to the direction of the force vector. But we can connect a coil to the voltage source, which will drive a current through the coil, which makes a magnetic field that moves a meter needle coil against a spring.

Current: You can't count the electrons, so we use the same meter, with fatter wire, and measure the same magnetic field pushing on a meter needle coil.

How about resistance? You can't even measure it at all. The best you can to is to pass a current through it and measure the voltage. The resistance is defined as V/I. Whoops that is a math model. Now what?

So, did the emperical data change? Oh yeah. As we learned about the physical phenomena and the effects, we developed better measurement techniques. And that changed the data.

(Quote attributed to Einstein: If the facts don't fit the theory, change the facts.):roll:


Most times the calculated result. Here is an example: We have a 2500kva transformer. Calculated short circuit current is 60KA. We are going to buy 65KAIC breakers for the first switchboard. Do you really want to throw a bolted fault on the transformer and measure the SCC? Or do you want to believe the calculation from the model?

How about the breakers. Do you want to test them at 60KA? I hope not. They are probably not rated to open more than once or twice at rated fault current. I say believe the calculation from the model.


Okay, that's good. The IEEE learned a bit more about physics and changed the model parameters. Tell me, in the past have you just made a VD calc and believed the wire size it said you needed? Or did you install the wire, load it up and then go out and measure the VD? I've only measured one - issue with the AHJ and a firepump.


Hummmm .... I've always thought the egg had to mutate (or evolve). Understanding of the physics was not created.

Someone came up with a model (a theory). And then did the testing to show that the model was true more often than not, and also to test and understand the limits of applicability.

You made a comment about calculations not being accurate. That's true. All models of physical phenomena have assumptions and limits of applicability that affect the accuracy of the calculation. Then when one adds in the measurement error, measurement technique error, pure technical screwup, instrument error, instrument algorythm error, ain't nothing exact. Anything man made has a tolerance - even your emperical data.

So ends the philosophy of mathematic models according to cf
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All that you have said, I could not agree more. I really like the "testing of the AIC of breakers, Bravo! :)
 
Cold Fusion said:
The thread has changed to "Models of physical phenomena are a poor second to emperical data" Okay.

Warning: Philosophy discussion to follow - Escape while you can.

...
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I'm looking for my escape button. I seem to have misplaced it. It looks like a Staples "EASY" button but has "ESCAPE" written on it. If anyone knows where it is, please let me know. :confused:

Anyway, since I'm stuck for now... most of your response isn't within the paradigm of my statement. It is in essence, the proof is in the pudding... pudding in this case being the empirical data. I did not say calculations are pointless. At some point in theory development and deriving of the equations used for calculations, the latter had to proven valid... right! So just how were the equations proven correct. What establishes proof of adequacy, and or accuracy of a calculation for electrical phenomenon? (In my mind that's a rhetorical question, but you can reply if you so desire.)
 
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Smart $ said:
I'm looking for my escape button. I seem to have misplaced it. It looks like a Staples "EASY" button but has "ESCAPE" written on it. If anyone knows where it is, please let me know. :confused:

Anyway, since I'm stuck for now... most of your response isn't within the paradigm of my statement. It is in essence, the proof is in the pudding... pudding in this case being the empirical data. I did not say calculations are pointless. At some point in theory development and deriving of the equations used for calculations, the latter had to proven valid... right! So just how were the equations proven correct. What establishes proof of adequacy, and or accuracy of a calculation for electrical phenomenon? (In my mind that's a rhetorical question, but you can reply if you so desire.)
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Not that easily.

Read Wiki again: "It is important to understand that the outcome of empirical research using statistical hypothesis testing is never proof. It can only support a hypothesis, reject it, or do neither. These methods yield only probabilities."

The proof is in the math. If you can formulate a mathematical formula that takes ALL relevant components of the observable data then you found the solution and explanation of the data.

Empirical science is based on observation and data collection and various statistical modeling of the collected data, the trying to observe the relational pattern of the data and create the mathematical model around it so from a set of data and unknown can be calculated. There are often either negligible, unobservable or unnoticed influencing factors in play, so a formula is created that has a constant, or have certain approximation to the repeatable data, but note that it is KNOWN and ACKNOWLEDGED by scientists themselves that these are only produce scientific PROBABILITIES, not CERTAINTIES.

On the other hand theoretical science's goal is to formulate the mathematical solution THEN find the data that fits. The reason being is that math IS certain. Hence Einstein's saying. What he is saying that you are missing data, so change the data.


Peace out rockers:D
 
weressl said:
So you don't believe that the Universe is based on a mathematical model?!

That everything that exist is based on a concept, an idea?

Tha nature just happen to express a very complex, yet defineable - however hard and difficult is - and orderly system?!

Peace out rockers:D
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On no, here we go.
 
Smart $ said:
I'm looking for my escape button. I seem to have misplaced it. It looks like a Staples "EASY" button but has "ESCAPE" written on it. If anyone knows where it is, please let me know. ...
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Well, I keep mine in the bottom left hand drawer - right next to the scotch and the Prozac. You might look there.

Smart $ said:
... So just how were the equations proven correct. What establishes proof of adequacy, and or accuracy of a calculation for electrical phenomenon? (In my mind that's a rhetorical question, but you can reply if you so desire.)
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My response is pretty much a non-answer. I don't know. I don't do any theoretical physics.

Although I occasionally do some testing to see if a particular application is within the limits of a model. For those issues, the model calculations must repeatably predict the output, within the accuracy of the equipment. If I can get three tests in a row that match - I am usually ecstatic.

cf
 
weressl said:
So you don't believe that the Universe is based on a mathematical model?!

That everything that exist is based on a concept, an idea?

Tha nature just happen to express a very complex, yet defineable - however hard and difficult is - and orderly system?!

Peace out rockers:D
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When I was in my first year at secondary school (about 12 years old), roughly your equivalent of high school, we were about to start an experiment in a physics class. We had (or most of us had) done the homework.
It was on Ohm's law. We already knew all the arithmetic.
So, at the start of the lesson the science teacher asked what we were about to do.
"We are going to prove Ohm's law, sir" I said.
"No we certainly are not!"
I was chastised in no uncertain terms.
"Sir?"
"We may verify Ohm's law.

That difference, from over forty years ago, has stuck with me.
Proof is a nebulous thing.

And I don't believe the universe is based on a mathematical model. But that's seriously off topic.
 
weressl said:
Not that easily.

Read Wiki again: "It is important to understand that the outcome of empirical research using statistical hypothesis testing is never proof. It can only support a hypothesis, reject it, or do neither. These methods yield only probabilities."

The proof is in the math. If you can formulate a mathematical formula that takes ALL relevant components of the observable data then you found the solution and explanation of the data.

Empirical science is based on observation and data collection and various statistical modeling of the collected data, the trying to observe the relational pattern of the data and create the mathematical model around it so from a set of data and unknown can be calculated. There are often either negligible, unobservable or unnoticed influencing factors in play, so a formula is created that has a constant, or have certain approximation to the repeatable data, but note that it is KNOWN and ACKNOWLEDGED by scientists themselves that these are only produce scientific PROBABILITIES, not CERTAINTIES.

On the other hand theoretical science's goal is to formulate the mathematical solution THEN find the data that fits. The reason being is that math IS certain. Hence Einstein's saying. What he is saying that you are missing data, so change the data.


Peace out rockers:D
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You are talking of the methodology used in obtaining a physics and or mathematical model. However, both approaches use empirical data. This term does not mean one uses empirical science as the approach mechanism. Since you mentioned Einstein's quotation, as did CF, empirical data is the "facts" mentioned in his quotation. You should also know there are many that believe he was purposely being facetious when he made the statement.

From what you have posted on the subject so far indicate you likely support chaos theory. I do too, in part... but not to the extreme where the universe can be explained as an unequivocally orderly system. There will always be purely random events. And while some of the currently inexplicable observations may not elude us forever, we will never be able to explain or define all, at least not in this life.
 
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