120V from both legs

Has something

with respect to

Maxwell and many many other brilliant scientists have not commonly addressed each and every issue with the power grid.

this article does however, mentioning ONE source of harmonic distortion, there are dozens of others....and ALL of them, and generation, distribution and use of electric power IS an employment of Electro Magnetic Forces ......... emf.

This is about harmonic distortions and the broader power grid from EC and M's ezine....

Beyond that there are harmonic distortions that any large facility can feed back into the power grid, screwing things up... the utility companies just hate that....motors and transformers can both create unwanted harmonic effects.

Paragraph 2 of the following article addresses these harmonics and power grid issues

The solution, of course, is to suppress harmonics."

long article balance at URL above

Phil Scott

it befor

accept my

(more convenient to

in machines).

(Lots of incoherent drivel snipped)

I think the solution, of course, is to suppress Phil Scott!!

Plonk!

message

accident

grid

Charlie

and

find

things

harmonics

grid

inverter's

and

sap

drives', not motors.

input stages

drawn from the

Yes indeed this article uses only ONE example.. a relatively uncommon one at that...but states that the problem of harmonic feed back threatens ***half the power on the grid...!

The fact is that there are dozens of ways you can get harmonic feed back.... (all of that is EMF by the way.....its 'back' emf when it goes out onto the grid...*including from a common induction motor, computer power supplies and many different types of transformers...and its is utterly well known and established and published as well.

No single article is going to give all possible examples... this one though states the problem as massive even though it only gives a single example... the gentle reader is required to extrapolate such things.

One can say water is wet... without then requiring someone to go out and prove every spot in the ocean and water well to be wet....

There is a massive harmonic feed back problem that threatens to consume half the power on the grid by some industry estimates. That problem is not coming from a few VSD's...but from dozens of other sources ive been mentioning specifically..and that are commonly known and published about in the industry.. something our friend Charlie and his PhD waving pal who claim to be experts are denying... by posting irrelevant references on vars, issues and trying to spin terms.

not impressive...and thats getting a bit obvious dont you think?

(as we have

I have argued correctly that motors, transformers of many types and computer power supplies are among the culprits...and that is correct. This artilce gives a VFD example... one of a type...

an example does not comprise an entire set... that should be but apparently is not obious to some of those posting the NG. There are many causes of harmonics feeding back onto the grid... described accurately for what its by the term 'back EMF' as EMF is simply the anagram for Electro Magnetic Force...of which harmonics are included.

I am simply stunned that an industry PE and PhD are taking the ludicrous lines of argument they are in the face of this very obvious and utterly pervasive and well known situation with electrical power, its distribution and use.

The attached article is a bit clear on the scope of the issue.

voltage drops in

output voltage

distorted

loads is

emf' generated

harmonics are

an increasing

motor drive

is controlled by

motor, no moving

element. But

to the resistor

supply in the

your position that

when in fact it

harmonics in supply

electronics

systems by virtue of

All distortion tends to be non linear... there are many many causes... your view that 'back emf' does NOT leak back to the grid is of course CORRECT.... IF the power feed is balanced perfectly... but of course it isnt...so you get feedback...non linear, out of phase feed back...and this is quite common...and as Ive said not limited to motors, but involves all sorts of other equipment.

So this article while discussing ONE...also states the scope of the problem at 50% obviously with more than a single family of causes.

Do I need to prove enery square inch of the ocean is wet to you, before you admitits comprised of water?

Thats the ludicrous level some are arguing this point on...first by saying there was no such thing as harmonic feed back to grid... then now by claiming 'well its only this one source'...then trying to say its rare non linear or whatever.

please.

Phil Scott. Some industry estimates predict that harmonics will eventually consume up to 50% of the energy on the nationwide power grid-clearly anunacceptable situation.

Fascinatin ain't it?

message

:) That doesn't change the facts son. Putting your head in the sand and issuing insults is not the brightest tactic.

"Some industry estimates predict that harmonics will eventually consume up to 50% of the energy on the nationwide power grid-clearly anunacceptable situation."

Would you the full article and link? How about some more links using other examples of disasterous levels of harmonic feed backs onto the grid?

Feed back some self proclaimed industry experts on this NG said did not exist to any significant extent. sorry... that position is ludicrous.

Now we see an professional journal article describing it as a grid threatening problem... to the 50% level !!!... and you put your head in the sand and resort to insults?

It seems not just a few of the 'heavies' on this NG have no clue about this very basic, broad spectrum, and significant issue...and its many causes. Then after I had been polite for days pointing out that none of us knows everything about everything even in our specialty areas..and that there might be a tiny sliver of the situation worth looking into...these gentlemen resort to insults and adhominem attacks.... what a crew.

and industry 'experts' too.

That comes from getting a BSEE without a good grip on physics first.. then trying to lie your way out of it. the end result is the destruction of ones own brain.

Sorry... thats just how it is apparently.

Phil Scott

Is it possible that Dark Matter has gone to anger management class and then resurrected himself here?????

Funny, LMAO!!!

First EMF is a 'force' and all 'forces' are F=MA. Now it's a current, a harmonic, a circuit condition, a marketing program!!!

Can't you tell which of your lies is which???

YOU are the one using 'emf' in more and more generic terms. And no one has denied that harmonic distortions exist (another of your outrageous lies). What *real* engineers acknowledge is that harmonic distortions from solid-state motor drive systems is an issue. What we (the rest of humanity) claim is that *motors*, in and of themselves, do *not* generate significant harmonic distortions. But you're to obtuse to understand the difference between a *motor* and a solid-state *motor drive* system.

Harmonics are becoming an increasing problem. But motor usage is *not* the cause. Solid-state devices that behave in non-linear fashion used to

The very article you reference for your position clearly states "...Motor drives present a nonlinear load to the power grid feeding them. Characteristically the diodes in an inverter's input stage create harmonic distortion as they switch on and off."

See that sentence that starts with the words "Motor drives..."??? Not "Motors", "Motor drives" !!! Notice where they placed the letter 's'?? A "motor drive" is the solid-state controller that chops up the incoming voltage waveform to soft-start the motor. Or the VVVF controller that uses phase-control to convert AC to a variable voltage DC so that it can be inverted back to a variable frequency AC at a constant volts/hertz ratio.

It is the increased usage of these solid state *motor drives* that has caused some concern. But the article you reference is seven years old now and new solid state motor drive controllers have design changes to limit the harmonics generated in them.

The fact that you can't tell the difference 'boggles ones mind'. Of course this just shows how deplorable your English reading comprehension skills are.

daestrom

No, that is *not* what they have been saying. Your reading comprehension skills are terrible. What we *all* have been saying is that induction motors do not create any appreciable harmonics. We have also said on more than one post that harmonics *are* caused by non-linear loads.

Trying to win a debate by misquotes and lies is childish.

You've quoted the same article in many of your posts now. Notice that it is seven years old? Has this harmonic distortions epidemic you keep ranting about reached the 50% level yet? Is seven years 'soon'?

Yes, their 'spin definitions' come from university texts and IEEE standards. Yours comes from some vague hand-waving and 'it is well known in the industry'.

Lies. They have not denied issues about harmonics, merely that induction motors are *not* a significant source of harmonics. You can't even read. The shift of the predominant loads on the power grid from simple induction motors and resistive heating/lighting to more and more solid-state, non-linear devices (including computer power supplies, electronic-ballasted fluourescent lighting, and solid-state motor controls) is the cause for the increase in harmonic pollution concerns.

Read the rest of your article and you can see in the third paragraph that the common approach to suppress the harmonics from a motor drive is to install filters between the power line and *THE INVERTER*. Because it is the motor drive's *inverter* that creates the harmonics. Not the induction motor connected to the unit, the *inverter* inside the motor drive. And in the final paragraph, "Harmonic distortion in ac industrial motor DRIVES [emphasis added] is a common, but correctable problem."

You're ranting about harmonic distortion as if it will reach epidemic proportions and bring down the grid, yet your reference says it is "a common, but correctable problem." To paraphrase a lesson for all first-year law students, "Don't use a reference to support your position unless you know what it says."

daestrom

Article is seven years old, yet the grid doesn't lose even 25% yet to harmonics. Seems some predictions are worse than others.

Common induction motor, no. Transformer, not internally. Computer power supplies, definitely. Electronic ballasts, yes. Solid-state motor drives, yes.

Harmonics are well known. But it is also 'well known' that induction motors and transformers are *not* significant creators.

Problem is, you've extrapolated from non-linear devices in motor drives to

But most of us know enough to stop the extrapolation when it goes too far. One can say *water* is wet, but you are taking that as proof that the floor is wet without knowing if there is water on it.

No, the problem isn't 'massive'. It is easily correctable (according to your own article's last paragraph). It has existed for at least seven years and yet the power grid stands. The problem *is* from VSD's (and there are a lot more than 'a few' now). It does come from many sources (and those sources are increasing), but it does *not* come from induction motors or transformers.

Perhaps you are 'stunned' because the facts about motors not creating significant harmonics has shaken your personnel beliefs? If you can't tell that different types of electrical loads have different characteristics and

Produce a reference that explicitly states that an induction motor, operating on the line creates significant harmonics. You will have a long and fruitless search. The reason your search will be in vain is because induction motors do *not* create significant harmonics. You've extrapolated one problem into areas where such extrapolation is no longer valid.

No, but you need to prove that all liquids are water before you can convince me they are all wet. That's the kind of ridiculous extrapolation you've done with this. Motor drives are a source of harmonics, so you've extrapolated that all sorts of things create harmonics. Since you don't understand the math and physics involved, you've extrapolated to areas/items that don't create significant harmonics.

Again with the poor reading comprehension. Your article describes one source of harmonics, solid-state drives. There are, of course, many, many others. But that doesn't include induction motors. Computer power supplies, light dimmers, electronic ballasts, there are many sources of harmonics. But resistors, induction motors, transformers, and incandescent lights are *not* sources of harmonics.

The article singled out solid-state motor drives as significant because the number of such drives is growing rapidly (it isn't just some 'rare few' anymore). And because of the amount of power that flows through them (often in the MW range) compared to other solid-state devices (often in the watt range), they in particular convert a lot of power into harmonics.

And if you didn't know what we meant by 'non-linear loads', you should have just asked (or followed your own advice and used google). The term is used to describe loads whose conductance varies non-linearly with the applied voltage. A simple diode is a perfect example. Saturable reactors, SCR's and other 'gated' devices are others. Because of their varying conductance, the current waveform through them is not a sine wave even though the applied voltage is. *ALL* such non-linear devices will create harmonics in the current waveform when an AC voltage is applied to them. When you take the current waveform produced and convert it to the frequency domain you will find it rich in harmonics. IF the harmonic currents are large enough, they can cause significant distortion in the voltage source by acting through the voltage source's internal resistance/reactances.

So you see, 'non-linear loads' are not some 'rare' or vague item. They are computers, televisions, compact fluourescent lights, solid-state drives, stereo systems, digital clocks, and almost any other electronic item (if it has an internal DC power supply, it probably produces some harmonics). Most such loads do not distort the supply voltage significantly because the amount of harmonic current is small and the internal resistance/reactances of the voltage source are also small. But if the harmonic currents are large (as the case with large motor drives), then even the small internal resistance/reactances of the voltage source will develop significant voltage distortions from the harmonic currents flowing through them.

It is the increased usage of such devices that has been cause for concern. But again, as your own reference points out, the problem is easily correctable.

daestrom

message

metering

totally

comprehension

induction

also said on more

loads.

you mentioned that rarely, then when you did you asserted that it was NOT significant problem to the grid.... sorry. it IS a very significant problem to the grid.

Furthermore Charlie and his PhD waving friend tried for a time to assert that there were no back emf issues from motors onto the grid...........bzzzzzt that was wrong too. Then all of you have chosen to become abusive in response.

not impressive. But it is telling.

estimated

Notice that it is

keep ranting

emf

Harmonics

IEEE standards.

known in the

will

have

record

and

not

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few

used?

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can't even read.

simple induction

solid-state,

electronic-ballasted

the cause for the

grid

things

paragraph that

drive is to

Because it is

Not the induction

drive. And in

motor DRIVES

epidemic

it is "a

for all first-year

position unless you

Notice that it is

keep ranting

You guys are simply amazing...its a top rated industry source...and now you expect the article (one among hundreds) is not valid unless its written yesterday maybe? thats cute. You challenge me to find a reference..then when I present one you want it written yesterday...or Charlie wants one that gives the math all 15 dozen sources of back emf harmonics onto the grid...and assumes the single example given is ALL Of it...even though the magnitude of the problem and common sense clearly shows otherwise.

NOW apparently because you dont know anything about the problems on our grid you assume that there are none of this nature because the single comprehensive white paper Ive found on the issue wasnt written with a year or so.

Look son.... Newton produced his equations regarding gravitational forces over a century ago... gravity still applies... back emf harmonics on the grid are equally well known... they apply regardless.

what do you want do now, claim that unless someone wrote an article on the situation yesterday that the previous 15,000 papers are invalid just because you personally have no clue...

amazing

emf

Harmonics

IEEE standards.

known in the

will

have

record

and

not

trying

few

used?

that induction

can't even read.

simple induction

solid-state,

electronic-ballasted

the cause for the

grid

things

paragraph that

drive is to

Because it is

Not the induction

drive. And in

motor DRIVES

epidemic

it is "a

for all first-year

position unless you

message

see?

a current, a

All forces ARE F=ma if they are moving its kinetic.. when stalled its potential, (as with a coiled spring or water held high in a bucket)...

It is apparent that you had not done well in your physics classes.

You will however garner the admiration of the abusive idiot contingent on the NG..sadly including some guys that should know better. Have a win pal.

Those however with a cleaner view of life have seen your arguments for what they are...Yours quite a new notches more well founded (but still spun) than Charlies

Oh yes... and in case you think you can run me off...forget it.. I will stay on the issue and the NG until its obvious to one and all, regardless what the issues are and who it was that tried to spin thier way out of it.

I will gather more references and post those until you three folks have no way to go but call me names and snip the articles, or claim they were not written lately enough to suit you..or that Newton is DEAD...therefore is laws no longer apply.

and you can keep that up.

and those of like mind will offer moral support for a while... but in the end... they know, as you do now down deep that you three were unware of the magnitude of the harmonics feed back issues onto the grid.

And that in itself is fine...there must be 15 billion things I have no clue on myself....but spinning to try and make ones lack of information valid simply screws up the persons own mind.

You may want to mediate on that...its rampant in the engineering business and makes that environment a real detriment to life (see the NASA study on shredded heart muscles traced to this crap in thier offices.)

Phil Scott

description

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of

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rest of humanity)

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the difference

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fashion used to

computer power

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them.

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drives..."??? Not

letter 's'?? A

the incoming

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it can be

volts/hertz ratio.

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years old now

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mind'. Of course

comprehension skills

Ah Daestrom! Its great to see you noticing the harmonics problem on the grid !!... I knew you had some integrity...it showed in spots of your previous arguments....close to 25% is it already?

Now thats an issue!

Tell Charlie...and his friend waving the PhD... that will be 'exciting'.

Progress.

Phil Scott

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easily

Phil - here are some quotes and added comments

-- Added comment -the thesis deals with the topic of analysis of the harmonic load flow for a power system with harmonic sources--i.e - finding out what is actually going on when there are harmonic sources at various points on a system. ...... "The subject that I was responding to was power factor correction and some of the claims that you have made with respect to the reason for this and claims as to its benefits." .... Comment: this delineates my targeted response.

Did you actually read the above?

-----

--------------

....... Kelly answered: "That was my typo- I thought that I had caught and corrected it befor sending -Yes - it does mean "electromotive force" Please accept my apologies."

Comment: rechecking through the net- emf and back emf are given in the sense that I calim- standard terms.

--------------

After all this you FINALLY came out with what YOU define as emf and back emf. Thank you for that.

The fact that your definition is yours alone and is contrary to the definition used in all the literature doesn't appear to bother you. You have simply ignored the evidence with respect to these terms. In addition, the definition that YOU use is already pre-empted for mechanical forces of electromagnetic origin -in power systems and machines it generally is restricted to the magnetic part of the Lorentz force (which has no mass or acceleration term). There are deeper meanings in the physical sense but in terms of conditions in a power system- it boils down to this. It is true that there is now a use of the term "EMF" (F for field- shades of Maxwell) which the non- technical use to lump electric and magnetic field boogiemen together but that is obviously not what you meant (Consider that a complement).

However, you have FINALLY made it clear that what you are dealing with is electronic motor drives. Goodie. I have never denied the harmonics generated (see quotes) in these motor drives and neither has Charles who referred to IEEE standards on harmonic content. . The source of the harmonics is the fact that these drives do not produce sinusoidal voltages and currents. Your "technical" reference is not really a technical reference-I would classify it as an "info-mercial" where firstly facts are presented (along with scare tactics "some say that .. 50%..." which are like "some say the sky is falling"- giving rise to the questions: "who are the some?" and "what is the basis for this?") and in later paragraphs- lo and behold- a particular company's harmonic filters are presented as the solution. The combination is suspect. If this is a top quality reference - God help us. This article was in 1997 - there are IEEE papers and working groups dealing with this since the 70's. The thesis that I referred to was in 1996 and the author had, at the time, and still has, a very successful Industrial power system consulting company so he is not in the least unaware of the problems. The info-mercial provides no new information. The concept of harmonic filtering for rectifier/inverter usage in power systems has been around over

If you had said, in the first place, that electronic motor drives present harmonic problems affecting both the grid and the motor, and that corrective measures are needed, then you would have had no adverse comments as that is true. You didn't. What you did say is another matter and that is the problem. . 'Nuff said

LIAR!!!!!!!!

I said, "..., yet the grid doesn't lose even 25% yet to harmonics." I did

Another example of your complete inability to read and comprehend the English language.

NO!!! I did *not* say it was close to 25%, I do *not* have to tell Charles anything, and the only 'progress' being made is you are proving more and more with each post what an ignorant, uneducated fool you really are. You can't comprehend what you read.

daestrom

Thank you. Would you please comment on the following view? One hears it said back emf subtracts from applied voltage, but if applied voltage to the motor is constant from start-up to steady-state then there cannot in reality be a back emf voltage. Only in theory. However one can measure that current reduces from start-up to steady-state, so the difference must be back

Ib = E/R - E/Z

Say E=120 volts, R=10 ohms, Z= 50 ohms then back current = 9.6 amps.

My the same rational then one could calculate back power.

Northstar

Thank you.

Northstar

message

integrity...it

is

harmonics." I did

well errrr..... then...what figure did you mean to toss out there (25% was close btw)... 2% maybe?

Now look becoming abusive is not really making your point. Could you clarify then on this 25%.. .. my 40 years in the business shows 25% not to be a bad guess at all... but it does vary hour to hour, and seasonally.. sometimes under 5% sometimes to grid failure levels well over 25% and that depends on where a particular user is on the grid...down line from a huge motor load is the worst.

Its good to see you guys finally acknowledging the broader problem, a combination of vars, back emf harmonic distortion, low voltage, phase imbalances, line to neutral variable phase to phase...etc.

Progress.

Good talking with you

Phil (the lying bastard) Scott

comprehend the

be

to tell Charles

proving more and

really are. You

You should really take a course in reading comprehension! I said, and I still say, that back emf from induction motors does not affect the grid. Period. It is 100% correct. You are the only person in the entire world using your definition of emf. I said over and over that vars were a problem, best corrected at the load of course. I also said that harmonics are a problem, but not from induction motors because induction motors produce such low values of harmonics. Adjustable speed drives and other power electronics devices are the prevailing sources of harmonic currents. They are not emf, current, not emf, current...perhaps if it repeated often enough you will understand. I also did not say anything about unbalance, you did. I said under fault conditions, a motor can act as a generator and thus feed fault current. Pay attention. Get a dictionary. Have someone read posts to you if necessary.

By the way, I checked several college level physics books today. All of them define emf as a voltage. And yes, emf can exist with no current. Farady was able to prove this many, many years before you were born.

You can disagree with my if you like, but do NOT lie about what I say. It shows a very low level of intelligence on your part.

Charles Perry P.E.

message

were

end

spin it

is

and

said, and I

affect the grid.

entire world

oh please you typed earlier that adding pf correction capacitors to three phase motors was a waste of money...a black box con or whatever.. you blew that horn long and hard from many different angles...now you are back peddling.

thats fine.

induction motors

drives and other

harmonic currents.

repeated often

about unbalance,

a generator and

Have someone

yer spinning bud.. trying to reverse your original assertions of no problem with feed backs and distortions to the grid from end users and I mentioned motors,and transformers of many sorts. (that includes many forms of VSD's)

today. All of

no current.

were born.

You have not grasp the nature of potentials and the fact of numbers of electons needed to create a potential.. that changes of course dramatically with voltage costant.

you have not integrated you knowledge base is all... you are seeing these things as discretely separated because they calc well that way...but actually all of this is entirely and completely integrated

what I say. It

You may assert what you will.... ones demonstration is what is relevant.

Phil Scott