Power Triangle Challenge

Merry Christmas

Besoeker3

Senior Member
Location
UK
Occupation
Electrical Engineer
I haven't looked at the numbers, but it may be proof for that one drive. That doesn't mean it works for all drives. Proving that would require a general argument along the lines of what Carultch or I gave.

Cheers, Wayne
Yes, it is proof for that drive. And for a good many others. They were designed, manufactured, and put into operation. Individual drives with specific requirements. A particular application was in the water industry which required no negative efficiency tolerance. It's a bit of a challenge.
Anyway, that's what what I did for a living.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Yes, it is proof for that drive. And for a good many others. They were designed, manufactured, and put into operation. Individual drives with specific requirements. A particular application was in the water industry which required no negative efficiency tolerance. It's a bit of a challenge.
Anyway, that's what what I did for a living.

Much Respect to you, more than half of that takes exceptional talent, skill and commitment. :)
 

myspark

Senior Member
Location
SCV Ca, USA
Occupation
Retired EE
Ironically the only proof you’ve demonstrated is your unconventional and incredibly low standard of proof.
The comparison table is totally relevant to your musings that invariably don’t increase the quality of electrical engineering concepts. . . but it does have its relevance to the discussion.

Yes, the table represent only small details. . . but it is particularly pertinent that leads us to the heart of the question.
And then you concluded that the response is “low quality”.

How on earth could anyone determine whether the line of thought is being carried through.
I did some close observations on this exchange. . . but as I keep track of what’s being said—I can admit that this has devolved into something that’s almost glorified drivel.
The table (as posted by Besoeker) explicitly make a clear comparison between the three fundamental concepts namely:

kW
kVA
kVAr

kVAr and its legitimate inclusion in power calculation did not come to being--until a Romanian electrical engineer in 1930 did his experimentation.
He proposed a “valid” unit of measure that resulted in the unit so called kVAr. He initially proposed the unit kW (watts) but it was already taken. It was agreed to by IEC to use kVAr.
His name was Constantin Budeanu,

I appreciate the intense inquiry and even call this as a “challenge” to demonstrate one’s know how.
However. . . I don’t consider the idea (in this context) of the word challenge in improving everyone’s comprehension and the display of expertise that you insist.
Your narrative --in terms of how you presented it --is simply an instigation or antagonization by saying to another engineer “ I dare you explain such a fundamental concept”.

Up to what end? Am I going to be rewarded or get a quarter million dollar job if I get the answer?
If not--why even bother.

Most of us have been or no longer actively engaged in the practice of the profession. . . and would no longer care what implication CURRENT/POWER would have if you apply variables in reaching for an answer or initiate a solution in a quadratic equation.
Einstein was quoted:
Education is what is left after everything else is forgotten.
It is still true in my case.
 

xptpcrewx

Power System Engineer
Location
Las Vegas, Nevada, USA
Occupation
Licensed Electrical Engineer, Licensed Electrical Contractor, Certified Master Electrician
The comparison table is totally relevant to your musings that invariably don’t increase the quality of electrical engineering concepts. . . but it does have its relevance to the discussion.

Yes, the table represent only small details. . . but it is particularly pertinent that leads us to the heart of the question.
And then you concluded that the response is “low quality”.

How on earth could anyone determine whether the line of thought is being carried through.
I did some close observations on this exchange. . . but as I keep track of what’s being said—I can admit that this has devolved into something that’s almost glorified drivel.
The table (as posted by Besoeker) explicitly make a clear comparison between the three fundamental concepts namely:

kW
kVA
kVAr

kVAr and its legitimate inclusion in power calculation did not come to being--until a Romanian electrical engineer in 1930 did his experimentation.
He proposed a “valid” unit of measure that resulted in the unit so called kVAr. He initially proposed the unit kW (watts) but it was already taken. It was agreed to by IEC to use kVAr.
His name was Constantin Budeanu,

I appreciate the intense inquiry and even call this as a “challenge” to demonstrate one’s know how.
However. . . I don’t consider the idea (in this context) of the word challenge in improving everyone’s comprehension and the display of expertise that you insist.
Your narrative --in terms of how you presented it --is simply an instigation or antagonization by saying to another engineer “ I dare your explain such a fundamental concept”.

Up to what end? Am I going to be rewarded or get a quarter million dollar job if I get the answer?
If not--why even bother.

Most of us have been or no longer actively engaged in the practice of the profession. . . and would no longer care what implication CURRENT/POWER would have if you apply variables in reaching for an answer or initiate a solution in a quadratic equation.
Einstein was quoted:
Education is what is left after everything else is forgotten.
It is still true in my case.

The challenge posed in the OP was not about a comparison table. As far as this discussion is concerned, there is nothing particularly interesting about numerical values.

I still don’t understand what that table of values is trying to convey. If they are only measured or calculated instantaneous kW, kVAr, kVA, pf values specific to a piece of equipment, they are irrelevant to the challenge because in of themselves, they don’t provide insight into the questions asked.

The solution was already posted. Two other engineers arrived at the same result independently. They seemed to have understood what was being asked and even explain their result. What they didn’t do was say the proof is there shame on you if you don’t see it.

Everyone has their own opinion. If you don’t see any value in this challenge because you don’t extract anything from it, I’m totally ok with that. I personally get value out of this kind of exercise and I suppose this discussion is for others who can also do the same.
 
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myspark

Senior Member
Location
SCV Ca, USA
Occupation
Retired EE
The challenge posed in the OP was not about a comparison table. As far as this discussion is concerned, there is nothing particularly interesting about numerical values.

I still don’t understand what that table of values is trying to convey. If they are only measured or calculated instantaneous kW, kVAr, kVA, pf values specific to a piece of equipment, they are irrelevant to the challenge because in of themselves, they don’t provide insight into the questions asked.

The solution was already posted. Two other engineers arrived at the same result independently. They seemed to have understood what was being asked and even explain their result. What they didn’t do was say the proof is there shame on you if you don’t see it.

Everyone has their own opinion. If you don’t see any value in this challenge because you don’t extract anything from it, I’m totally ok with that. I personally get value out of this kind of exercise and I suppose this discussion is for others who can also do the same.
Your mode of fielding a question is a rhetorical in nature that is not aimed to secure an answer. It is using a technique of an often used trickery in exchange or debate called “gotcha.”colloquially.

An old way of giving a response without much rationale.
We educate ourselves to acquire some skills or tools to have a fighting chance of survival in a chaotic world.
Not through trickery. . . it’s a jungle out there.

The numbers that were posted on that table were only for the purpose of authenticating the relationship of those units eg. power source, power consumed and power that is available to do a certain work.

And then you mentioned INSIGHT that is missing in the post. The reader is provided the necessary information that could provide a road map that will lead to an answer.
INSIGHT comes from the reader--and that is you.

Provide your insight for the poster so he can elucidate things that you as reader doesn’t understand.
It seems that your forte centers on asking rhetorical questions that don’t necessarily need an immediate answer.
They are engineered questions meant to expose the other party’s flaw in his arguments. . . a cheap strategy.

This is what we call formally as EPIPLEXES. . . an interrogative figure of speech. This is the type of questioning that although requires a response. . . it is mostly argument-via-questioning.

EPIPLEXES is basically confrontational and reproachful at best.

As for me I am contented in having my morning coffee--watching the opening of the stock market-- keeping an eye on the numbers if I’m losing my shirt or gaining valuation of my portfolio.
 

xptpcrewx

Power System Engineer
Location
Las Vegas, Nevada, USA
Occupation
Licensed Electrical Engineer, Licensed Electrical Contractor, Certified Master Electrician
Your mode of fielding a question is a rhetorical in nature that is not aimed to secure an answer. It is using a technique of an often used trickery in exchange or debate called “gotcha.”colloquially.

An old way of giving a response without much rationale.
We educate ourselves to acquire some skills or tools to have a fighting chance of survival in a chaotic world.
Not through trickery. . . it’s a jungle out there.

The numbers that were posted on that table were only for the purpose of authenticating the relationship of those units eg. power source, power consumed and power that is available to do a certain work.

And then you mentioned INSIGHT that is missing in the post. The reader is provided the necessary information that could provide a road map that will lead to an answer.
INSIGHT comes from the reader--and that is you.

Provide your insight for the poster so he can elucidate things that you as reader doesn’t understand.
It seems that your forte centers on asking rhetorical questions that don’t necessarily need an immediate answer.
They are engineered questions meant to expose the other party’s flaw in his arguments. . . a cheap strategy.

This is what we call formally as EPIPLEXES. . . an interrogative figure of speech. This is the type of questioning that although requires a response. . . it is mostly argument-via-questioning.

EPIPLEXES is basically confrontational and reproachful at best.

As for me I am contented in having my morning coffee--watching the opening of the stock market-- keeping an eye on the numbers if I’m losing my shirt or gaining valuation of my portfolio.
I can assure you there's no trickery, I certainly did not invent the power triangle and I am in no way a gatekeeper to the solution.

To be perfectly honest with everyone, this derivation was never covered in my undergraduate program, and something about that really bothered me. I felt cheated, so I was compelled to delve deeper into the origins of the power triangle concept rather than blindly accept it as given.

Insight can be found within the derivation in post #40. All I can say is I think you are over analyzing this.

An interesting reaction I didn't expect was those who don't agree with the way this challenge was posed (including those who feel attacked by it) didn't bother posting a solution, but instead were more concerned about telling me how content they are with their present understanding. So be it. Be content. This is obviously not the thread for you.
 

myspark

Senior Member
Location
SCV Ca, USA
Occupation
Retired EE
I can assure you there's no trickery, I certainly did not invent the power triangle and I am in no way a gatekeeper to the solution.

To be perfectly honest with everyone, this derivation was never covered in my undergraduate program, and something about that really bothered me. I felt cheated, so I was compelled to delve deeper into the origins of the power triangle concept rather than blindly accept it as given.

Insight can be found within the derivation in post #40. All I can say is I think you are over analyzing this.

An interesting reaction I didn't expect was those who don't agree with the way this challenge was posed (including those who feel attacked by it) didn't bother posting a solution, but instead were more concerned about telling me how content they are with their present understanding. So be it. Be content. This is obviously not the thread for you.
Whenever you post a comment on the web, you become fair game for everyone. So, it is not fair to say "this thread is not for me"

And when you refer to answers of other posters to support your argument, you are committing a fallacy called in latin ad misericordiam. Using another argument whether true or not to validate your argument.

The problem here is some responses are their humble opinions.
Just as the nature of opinions . .they are mere conjectures, guesses, and suppositions.
Toothless. . ..nothing to bite with.
 

xptpcrewx

Power System Engineer
Location
Las Vegas, Nevada, USA
Occupation
Licensed Electrical Engineer, Licensed Electrical Contractor, Certified Master Electrician
The problem here is some responses are their humble opinions.
Just as the nature of opinions . .they are mere conjectures, guesses, and suppositions.
Toothless. . ..nothing to bite with.
Fortunately for this discussion the only thing needed to participate was a mathematical proof/derivation based on physics. Not a psychological opinion.
 

myspark

Senior Member
Location
SCV Ca, USA
Occupation
Retired EE
You have been given the proof but your belligerence is getting the best of you.
Confrontational from beginning to the end.
Need some brush up on your debating skill if you have some.
You said you lack the total understanding of the power triangle. That's understandable. . . .it can happen to anyone. I don't look down on anyone with misgiving.

If I truly believe in those words. . . perhaps rewording your question in the form of real question and not daring anyone with the tone of being antagonistic.
 

xptpcrewx

Power System Engineer
Location
Las Vegas, Nevada, USA
Occupation
Licensed Electrical Engineer, Licensed Electrical Contractor, Certified Master Electrician
You have been given the proof but your belligerence is getting the best of you.
Confrontational from beginning to the end.
Need some brush up on your debating skill if you have some.
You said you lack the total understanding of the power triangle. That's understandable. . . .it can happen to anyone. I don't look down on anyone with misgiving.

If I truly believe in those words. . . perhaps rewording your question in the form of real question and not daring anyone with the tone of being antagonistic.
you're being too sensitive but you are entitled to your feeling/opinions nonetheless
 

__dan

Senior Member
The school I went to there was no vector math at all. No geometry since HS and it does not even count towards the degree. Everything was transform functions and transforms, e exp it. The i is buried in the exponent. No explanation why and it's not obvious to me. No vector math, very rarely see sinewaves. I recall getting laplace transforms drilled into me. That was the precomputer era. School's computer ran on punch carsds (had that course in assembler and Pascal on punchcards), with a phone line connection to the mainframe on campus. Pencil and paper only, a few years too early for Spice.

Their courses have improved a lot since then. They have a complex math class I want to take (doesn't count towards the degree requirement).

i has the sinewave buried in there, in itself, along with a factor for some displacement in a field subject to a restoring force.What is it in the underlying physical reality that drives the model behaviour. Tesla said we would hook our machinery right into the wheelwork of nature.
 

Carultch

Senior Member
Location
Massachusetts
The school I went to there was no vector math at all. No geometry since HS and it does not even count towards the degree. Everything was transform functions and transforms, e exp it. The i is buried in the exponent. No explanation why and it's not obvious to me. No vector math, very rarely see sinewaves. I recall getting laplace transforms drilled into me. That was the precomputer era. School's computer ran on punch carsds (had that course in assembler and Pascal on punchcards), with a phone line connection to the mainframe on campus. Pencil and paper only, a few years too early for Spice.

Their courses have improved a lot since then. They have a complex math class I want to take (doesn't count towards the degree requirement).

i has the sinewave buried in there, in itself, along with a factor for some displacement in a field subject to a restoring force.What is it in the underlying physical reality that drives the model behaviour. Tesla said we would hook our machinery right into the wheelwork of nature.

I'm very surprised that the coursework taught you Laplace transforms, but not vector math.

3Blue1Brown does a great job of putting it all together, in terms of the math behind why an exponential is connected to the sine wave, the significance of the number e, and the value of having a number system with imaginary and complex numbers. Look up some of his videos on the topic.

The relationship between these two function families is not immediately obvious, as they seem completely unrelated. It takes about a year of Calculus, plus the basics of imaginary and complex numbers, to understand. To summarize why they have this connection, it has to do with both functions having a Taylor series of a similar form. A Taylor series is a polynomial that seeks to match the position, slope, curvature and other properties of the original function at a reference point, in order to evaluate the rest of the function. When x is a real number, e^x's Taylor series has all positive terms and converges on the exponential function. When you replace x with the imaginary number (i*theta), you end up getting an alternating series of terms that converges on a combination of sine and cosine. The real number projection of the complex number from this calculation gives you cosine, and the imaginary projection gives you sine.

An infinite series is precisely what is behind how your calculator and computer evauate the trig functions. Not necessarily the Taylor series specifically, as there are other infinite series that are more efficient to calculate. The Taylor series is usually the first kind of infinite series that is introduced, due to it being the most intuitive as to how it is formed.
 

__dan

Senior Member
In the underlying physical reality, first guess would be that it is some type of dipole, spinning dipole, so the sinewave description is natural and obvious. The i is a vector rotation operator by 90 deg, guarantees it is orthogonal, Then there's the field, field polarization, the aether, EM. Vector representation seems obvious.

A geometric model makes sense (if it works). Mills models the electron as a 2d great circle, infinitely thin 2d, which can move without radiating.

Yeah we had no vector math and even now it's a specialty class. We would look at the circuit, write a transfom function from it, and then it was a laplace transform from there. I believe they call it an 'analytical method'. It it not intuitive. There is nothing I look at that I want to write a transform function for. I want a geometric model that represents the underlying physical reality.
 

Carultch

Senior Member
Location
Massachusetts
In the underlying physical reality, first guess would be that it is some type of dipole, spinning dipole, so the sinewave description is natural and obvious. The i is a vector rotation operator by 90 deg, guarantees it is orthogonal, Then there's the field, field polarization, the aether, EM. Vector representation seems obvious.

A geometric model makes sense (if it works). Mills models the electron as a 2d great circle, infinitely thin 2d, which can move without radiating.

Yeah we had no vector math and even now it's a specialty class. We would look at the circuit, write a transfom function from it, and then it was a laplace transform from there. I believe they call it an 'analytical method'. It it not intuitive. There is nothing I look at that I want to write a transform function for. I want a geometric model that represents the underlying physical reality.

You are correct that there is some type of spinning dipole. Magnets come as a north and south pair of poles, which is a dipole. Most of our electricity comes from rotating machinery in some form or another. Assuming it is the permanent magnet in the generator that rotates, and the pickup coils that are stationary, the permanent magnet would be the rotating dipole. The time-varying magnetic field, from the magnet poles rotating toward and away from the pickup coils, induces the voltage in the pickup coils per Faraday's law of induction. Because the magnets make complete cycles from north pole to south pole as they interact with the coils, you end up having to have a complete cycle of the time derivative of the magnetic field that induces the voltage.

The generator design will not necessarily have the permanent magnet as the thing that rotates. Some designs swap the roles of stator and rotor, so that the pickup coils rotate instead. There are also generators that forgo permanent magnets altogether, and are built with electromagnets that take the place of the permanent magnets.

It would be impossible to build a native DC generator, that doesn't rely on commutators or rectifiers to change from AC to DC. You would need an continuously increasing magnetic field inside the coil, to induce a steady DC voltage, and that is impractical to sustain. Therefore, there is no such thing as a DC generator that directly generates DC. AC is the native format of electrical power from a rotating generator. DC generators really start by generating AC, and either using the commutator as a mechanical switch to reverse direction, or the rectifier as a solid-state switching method.
 
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GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
You are correct that there is some type of spinning dipole. Magnets come as a north and south pair of poles, which is a dipole. Most of our electricity comes from rotating machinery in some form or another. Assuming it is the permanent magnet in the generator that rotates, and the pickup coils that are stationary, the permanent magnet would be the rotating dipole. The time-varying magnetic field, from the magnet poles rotating toward and away from the pickup coils, induces the voltage in the pickup coils per Faraday's law of induction. Because the magnets make complete cycles from north pole to south pole as they interact with the coils, you end up having to have a complete cycle of the time derivative of the magnetic field that induces the voltage.

The generator design will not necessarily have the permanent magnet as the thing that rotates. Some designs swap the roles of stator and rotor, so that the pickup coils rotate instead. There are also generators that forgo permanent magnets altogether, and are built with electromagnets that take the place of the permanent magnets.

It would be impossible to build a native DC generator, that doesn't rely on commutators or rectifiers to change from AC to DC. You would need an continuously increasing magnetic field inside the coil, to induce a steady DC voltage, and that is impractical to sustain. Therefore, there is no such thing as a DC generator that directly generates DC. AC is the native format of electrical power from a rotating generator. DC generators really start by generating AC, and either using the commutator as a mechanical switch to reverse direction, or the rectifier as a solid-state switching method.
1. I used to have a McCullough portable generator with a great heavy permanent magnet rotor. Only voltage regulation was via throttle control
2. Faraday's homopolar generator (fascinating beast) was, IIRC, a pure DC generator. With no commutator or rectifier. Look it up.
 
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