Re: Saturation in transformers.

>
>
> So you say, incessantly. Not one of your claimed customers has ever
> endorsed any one of your claimed products, and I am not surprised.
> You spend a lot of fools' money pretending to do what many
> manufacturers of excellent reputation do for a fraction of the
> price.

I make a living doing repairs, restorations, building complte new amps.

I have nothing I want to prove to a disbelieving person like yourself.

But I did wind ALL the trannies and chokes in the items at my website.

None of my customers would be seen dead posting here.

>
>
> >>
> >> > and the coil becomes a short circuit when the steels field
> >> > cannot
> >> > continue to
> >> > oppose the current flow of the current from the applied
> >> > voltage.
> >>
> >> No. Some time ago I pointed out an error in RDH. Perhaps you
> >> ignored
> >> me and failed to amend the diagram? The inductance does not
> >> plummet
> >> as depicted, but actually trails off more gradually as current
> >> increases.
> >
> > If you examined the current wave form as V across a winding is
> > increased,
>
> Blah de blah...obfuscation again. Wriggle, squirm.
>
> > you will find there is a sudden increase in the 3H after what is
> > called
> > the saturation
> > phenomena.
>
> Wriggle, squirm. The singular of phenomena is phenomenon, but better
> to avoid the wriggling, squirming obfuscation and just call it
> saturation. Once you arrive back on earth you may realise that it is
> necessary to define an arbitrary point in the process you describe
> at which you say the iron is saturated. It is not sudden like a
> switch. Look it up, but not in RDH because the diagram is wrong. Or
> perhaps it would help to look at the RDH diagram and try and see
> *why* it is in error.

You have not proven the RDH to be in error.

And you make silly comments about squirming and obfuscation,
but I leave YOU to get off your arse and go and observe something.


> As I have said several times, the best
> definition I have seen is the point at which the current spike is
> double the magnitude of the underlying current waveform. A more
> useful definition could be a particular proportion of distortion.

Depends on the core material.

Some say its when the 3H in the current wave exceeds 12% when the tranny
is fed from a
low Z source like the mains.

But you look, and you decide.



>
>
> > The iron appears to have magnetic store of energy to oppose the AC
> > flow
> > for *parts* of the cycle, ie, the top and bottom part of the wave,
> > so we
> > see
> > large current *spikes* where the coil acts as if it has become a
> > short
> > circuit
> > for part of the cycle.
>
> No. Once again, it is not a short circuit, ever. It is never a short
> circuit.

When the mains voltage can appear across the DCR of the winding wire of
the
primary for all or part of the wave cycle, it is considered that a
continuous or
part time short circuit condition.

So take you silly idea of never to some other group which
understands never.

> Since you are the one claiming to do loads of real
> measurements, perhaps you could say when you measured this short
> circuit?

Do your own observations, don't rely on me.



>
>
> > But for other parts of the cycle around the zero crossing region
> > the
> > iron energy is providing
> > some oposition to the flow of current in the wire.
> >
> > If you looked, you would know.
>
> Before I knew, I did look. But looking is not knowing, as you
> clearly demonstrate.

You refuse to look enough.

>
>
> >> The situation is exacerbated by what you, with your crazy notion
> >> of
> >> feedback, would call positive current feedback: as current
> >> increases, reactance falls, so current increases further,
> >> etcetera.
> >
> > There is no crazy notion of FB.
>
> Give you half a chance and you will invent one. Don't you see the
> parallel with your hopeless notion of triode "internal feedback"?

You are a real dumb brute of a fool if you cannot understand the NFB in
a triode.
Its been explained a thousand times here, but Professor Child had much
more
precise descriptions of it in T.E.Terman's Radio Engineering book of
1937.

I suggest you read a little more before saying leading professors of
radio
engineering got it all wrong.


>
> > Electro magnetics isn't easy to understand.
>
> It would help if you found out about algebra.

I know enough algebra.

>
>
> > But why does not a large current flow when you apply
> > a voltage across a coil?
>
> Er, it might, or might not, depending on the time, the resistance
> and the reactance.
>
> > The magnetic field the applied voltage sets up opposes the flow.
>
> No. The current sets up the magnetic field. Otherwise you wouldn't
> get the phase difference, clot.

There is a tiny magnetizing current in the no load condition
of most toroidal trannies.

The oppsition to the current flow is due to the high inductance of the
coil.
Ditto in an OPT, where at 1kHz, almost no current flow occurs at all
without a load.



>
>
> The changing magnetic field produces an opposing voltage, which
> opposes the applied voltage (not the current, which I suppose you
> mean by "flow"). The residual voltage drives the current through the
> winding resistance.

I see you don't design and build any trannies.

>
>
> In the case of a transformer, the current in the secondary produces
> a field opposing that produced by the primary. The residual field
> is, more or less, the same as that produced by the primary alone
> when the secondary is open circuit. Hence the transformer can be
> modelled by a resistance in parallel with an inductor made up of
> just the primary and the core.
>
> Such a model is generally accepted, and can be useful even up to the
> frequencies used for SMPS, where matters become more complicated
> because of core losses and skin effect. For the kind of frequencies
> and waveforms we are talking about, it is hardly a black art

Well since you know all about the black art of winding trannies,
go to it, no need to discuss anything with me.



>
>
> >> But, so considered, the feedback is less than unity so the result
> >> is
> >> finite...whereas with a short it would be infinite. In fact an
> >> equilibrium is reached for any given current, and reactance does
> >> not
> >> disappear as quickly as you think, or as RDH shows.
> >
> > I didn't say the L dissapears once a threshold has been reached;
> > but it
> > is as if
> > there is a sudden large reduction fall in inductance at
> > saturation.
>
> You said ***"short circuit"***. That is the point you are defending.
> A sudden fall, a large fall...neither of these is a short circuit. A
> short circuit is somewhere close to zero ohms.

See above.

> The effect you are
> trying to describe is not a short. The impedance falls quite
> quickly, the current rises quite rapidly, reaching by my adopted
> definition twice the instantaneous value which would flow if the
> iron remained magnetically linear.

Go observe a few trannies to examine the saturation behaviour before
spouting
all this stuff as if you really know.



>
>
> >> Of course there is also primary resistance, which remains
> >> unaffected, so that is two reasons why the coil does *not* become
> >> a
> >> short.
> >
> > Well when the inductance ceases to oppose the flow during the wave
> > cycles due to
> > saturation, the applied voltage to the primary tends to be a short
> > circuit current, ie,
> > the mains applied voltage sees only the DCR of the primary.
> > This situation *is* regarded as a short circuit.
>
> Squirm, wriggle, obfuscate. Let's just unpick it this time shall we?
> What is this "DCR" you have thrown in...like the "saturation
> phenomena (sic)" we saw before. It is a characteristic of your
> squirming obfuscation that you try to blind people with pathetic
> grandiose attempts at jargon.
>
> You mean resistance, don't you? By "DCR" you just mean resistance,
> yes? Resistance at DC? Have I worked it out correctly?
>
> As opposed to ACR perhaps? Do you perceive a difference between ACR
> and DCR? Perhaps it would help if you were to realise that it is a
> defining characteristic of resistance that it is the same for AC and
> DC? Surely if you pretend to make good transformers, you must also
> pretend to know the difference between resistance and reactance?
>
> So really you just mean resistance. Why then did you call it DCR?
> What is the purpose of this wriggling, squirming obfuscation?

DCR is the measured DC resistance of the copper wire in a coil.



>
>
> Because you just said that a resistance is regarded as a short
> circuit. By who, I wonder. You alone, in all the world, sadly.
>
> Let's look at that again...
>
> > the mains applied voltage sees only the DCR of the primary.
> > This situation *is* regarded as a short circuit.
>
> Did you really say that? Look, you even underscored the "is".
> Crikey. Worth another look...
>
> > the mains applied voltage sees only the DCR of the primary.
> > This situation *is* regarded as a short circuit.
>
> Should I bother any further with a conman who thinks that a
> resistance is a short circuit?

You fail dramatically yo understand one point all engineers agree upon.

Say a primary winding has a DCR = 40 ohms.
When the magnetic field collapses during part of the waveform due to
saturation,
ie the iron can no longer be increasingly magnetised to oppose the flow
of magnetizing current,
then the 240V of the mains sees the 40ohms of the DCR and a 6A flow
of AC current can flow during the saturation.

This is enough to blow fuses or melt down a tranny, cause loud hum, and
generally be a PITA.

Its SO obvious you know *** All about trannies, or you would have
explored this effect.


>
> And, what is more, it doesn't only see the resistance. It also sees,
> for much of the time, the full inductance of the transformer and,
> for that portion of the time when saturation occurs, it also sees a
> considerable remaining contribution to the inductance by the core,
> plus it sees the inductance of the windings as if there were no iron
> there at all. In addition, the apparent resistance it sees in the
> winding is modified by the core losses.
>
> Not a short then, is it?

The reactance during the saturation events drops to negligible levels.

Hence engineers call the sharp saturation current peaks that more easily
occurs in high µ material like the
GOSS coil of a toroidal tranny short circuits; the long circuit is the
one where there
is substantial inductance to always provide a high reactance to oppose a
high current flow.



>
>
> >> Further, you may notice that a saturated transformer gets hot. A
> >> short dissipates no power (only current, no voltage drop), so
> >> where
> >> do you think the heat is coming from?
> >
> > Two things, core losses, and copper losses.
>
> And how would they happen if the primary appears as a short?

Watts = I squared x R; so if the saturation currents are high,
then the power dissipated in heat are high.

> You
> haven't seen my point at all as usual. Can't have losses without
> power, can't have power without voltage, can't have voltage if it's
> a short. No matter how much I suggest it, you still haven't looked
> up Ohm's law.

I use Ohm's Law every day, and have considered it all along in this
discussion.

>
>
> >> > The very field in an inductor opposes the current flow...
> >> >>
> >> >> If you think of it as a load resistance in parallel with an
> >> >> iron-cored inductor with a given core and number of windings,
> >> >> it
> >> >> is
> >> >> the current through the inductor that produces the magnetic
> >> >> field,
> >> >> hence too much current leads to saturation.
> >> >
> >> > The too-much-current occurs after a voltage threshold hold has
> >> > been
> >> > reached.
> >>
> >> Only at a particular frequency (sigh...). Do you remember any
> >> school
> >> maths?
> >
> > See my formula.
>
> The one you got from RDH? Don't need to, it was burned into my brain
> aged about 13.
>
> > Seems to me my maths are better than yours.
>
> I can see how it seems like that to you.
>

Well make up your mind, either my formula is right or wrong.



>
> >> Remember the common questions that ask you to reduce an
> >> equation to its simplest form? Why was that an important skill to
> >> learn? Because it allows you to see the essential relationship
> >> without the complications of mathematical clutter and particular
> >> circumstance.
> >
> > The transformer equation is the simplest way to relate the design
> > parameters of a transformer.
>
> Maybe so, depending on what you are designing for. But the thread is
> not about how to design a transformer, but rather how to understand
> how transformers saturate. But you won't have noticed that in your
> rush to con another fool out of his money.

Only a true desperate FUCKWIT like yourself would, after the last 4
years of
discussions and refusals to ever do some real practical electronic
engineering
observations, make a statement to link me being a conman to
whether or not I understand magnetic behaviour.

get back to me when you have done the hard yards of observations of what
happens.
Or else STFU.

>
>
> >> In this case you would substitute voltage and frequency for
> >> current,
> >> and end up with a very simple formula. That would improve your
> >> basic
> >> grasp of the relationship, which would be true for *all cases*.
> >>
> >> Armed with this fundamental understanding, you can quite easily
> >> derive whatever practical formula you wish, depending on the
> >> particular problem you are addressing. If you are interested in
> >> frequency and voltage, then you can derive the formula you gave
> >> from
> >> RDH.
> >
> > I did derive my formula from what is in RDH4 and a few other old
> > books
> > that explain everything.
>
> You derived your formula? You mean you copied it from one of the
> zillion places it appears.

I didn't invent the standard tranny equation. Loftier minds than I did
Mine works for metric measurements, valid for me since I live in Oz
which
has metric measurements.
Using some imperial version would give you identical results as
spelled out in the examples in RDH4.


>
> > Often their explanations are totally incomprehensible.
> > Electro Magnetics was designed by the schitzoprenic brother of the
> > God Of Triodes, and this dude made the use of iron, wire, and
> > volts
> > to be as confusing as possible.
>
> I can see your problem...
>
> >>
> >> Fundamental understanding is, in other words, transferable.
> >> Without
> >> it, particular knowledge is just empty fact. That's why you have
> >> to
> >> keep reading the book...you lack the conceptual framework to
> >> construct your own thoughts.
> >>
> >> If you know the core, and how many turns on the windings, and how
> >> much current through each, you are home and dry. The only reason
> >> you
> >> need to drag voltage and frequency in is in order to calculate
> >> the
> >> current.
> >>
> >> You won't see what I mean, and neither will Phil. Oh well.
> >
> > I do wind much better transformers than I can buy from anyone.
>
> So you keep saying, but no-one who has bought one agrees. How would
> you know anyway? You don't test them properly. You don't even know
> Ohm's law.

Again you spit at someone who really knows a shirtload more than you.

>
>
> > My conceptual understanding levels are good enough.
>
> For conning fools out of their money, perhaps.

Again you show you've lost the argument.

>
>
> >
> > Phil knows more about it than you do, and he can explain it when
> > he
> > isn't
> > acting like a complete fukken idiot.
>
> Then check the last statement of his last post to me, where he
> finally admits to some approximation to the truth about current.
>
> My estimation is that he actually knows less than you, if that is
> any comfort. But he has had enough failed education to fake a
> different level of smartness.

Phil knows a truckload more than you do despite whatever
formal education he may/may not have sustained.

He finds it distressingly tedious to deal with your arguments
which are never backed up witjh any real observations or practical
experiences.

That's why he calls you all the names under the sun.
He sees you as a dumb cluck who rabbits on and on
but there is SFA to be learnt.

Its not very nice to be rude, but Phil can't help it when you provoke
it.

But next time you have a spare sunday, take a couple of trannies and a
variac
and explore the current flow in the unloaded condition.

You can do this using a 110V winding, and watch how the reactance
falls as Vin rises, and how inductance falls dramatically once you raise
the
Vin past 120V. be careful not to burn out the variac.

Patrick Turner.

>
>
> cheers, Ian

.