Talk:Transformer

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edit·history·watch·refresh Stock post message.svg To-do list for Transformer:

Here are some tasks awaiting attention:
  • Verify : More referencing needed
  • Other : Tease out 'History', 'Windings', and 'Cooling' sections in regard to liquid-immersed transformers' dual insulation and cooling roles Done. Sort of.

What about piezoelectric transformers?[edit]

The article doesn't seem to be so good, as long as it completely neglects the existence of the now ubiquitous piezoelectric transformers. — Preceding unsigned comment added by 88.19.228.43 (talk) 22:19, 29 October 2014 (UTC)

Since they work by an entirely different principal and have a completely different history, they should probably have their own page such as Transformers (piezoelectric). Constant314 (talk) 00:02, 30 October 2014 (UTC)
Agreed. Although they've been around for a decade or so they're still far from "ubiquitous". They're numerically common, but AFAIK in only one application: AC inverters for CCFL backlights. An article on piezoelectric transformer would definitely be a good thing. Andy Dingley (talk) 00:07, 30 October 2014 (UTC)

Ideal transformer[edit]

It shoud be noted that an ideal transformer is not only lossless but is is unable to save electrical energy like a coil. So there is no mutual inductance in it. --Wefo (talk) 14:30, 31 October 2014 (UTC)

Since ideal transformers don’t exist, it is not particularly important to debate this. But, just for fun: 1. Transformers don’t store energy in their mutual inductance, they store it in the self-inductance (a.k.a. magnetizing inductance). 2. Ideal transformers cannot store energy because their self-inductance is nominally infinite. You cannot store energy in an open circuit. An infinite inductance is indistinguishable from an open circuit so you cannot store energy in an infinite inductance. Actually, storing it is not the problem. The problem is getting the energy to go into an infinite inductance.Constant314 (talk) 22:18, 31 October 2014 (UTC)
Given a transformer without load. Then it behaves like a coil with [1]. You are nearly right with "Ideal transformers cannot store energy because their self-inductance is nominally infinite." but there is no inductance at all. There are simply equations, formulas, nothing else. Therefore a really precice definition in important. -- Wefo (talk) 21:47, 1 November 2014 (UTC)
I agree with you that it is meaningless to attribute internal structure to an idea transformer, but people do. But you can make it precise by starting with a linear transformer of the correct turns ratio and then taking the limit as the leakage inductance goes to zero and the self-inductance becomes unboundedly large. An ideal transformer doesn’t exist, but it is a useful artifice.Constant314 (talk) 00:46, 2 November 2014 (UTC)
This usefull artifice is shown in [2]. But it is to define properly. There is no self-inductance at all, and so it isn't usefull to make it "unboundedly large". -- Wefo (talk) 21:03, 2 November 2014 (UTC)
Just curious, what do you think no inductance means?Constant314 (talk) 00:08, 3 November 2014 (UTC)
You are right, it is really very curious, but the inductances in the picture are only "reminding" a transformer. Let us think, of a transformer 1:1. Then the rest of the picture shows the elements of replacement, but the ideal transformer is only dividing the circuits electrically. without the dividing the woud be almost nothing in it, only one link on the upper side and one at the lower: [3]. -- Wefo (talk) 01:02, 3 November 2014 (UTC)
The entire point of introducing the ideal transformer is to discuss what effects the transformer has on the external circuit without having to consider what is happening on the inside. Really all it requires are the two-port equations. But some people like to keep their inductances even if the are zero in the case of leakage inductance and infinite in the case of the magnetizing inductance. You could certainly say that there are no detectable inductive effects. Constant314 (talk) 21:50, 4 November 2014 (UTC)

Core losses[edit]

Greetings all,

Just a casual user here looking through the transformer article and noticed that there seems to be one or more formulas missing in the section about hysteresis loss. I don't have the knowledge to fix it, but perhaps someone else could have a look at it.

I've quoted the "problem" paragraph below....

Thanks!

Steve

Hysteresis losses

Each time the magnetic field is reversed, a small amount of energy is lost due to hysteresis within the core. According to Steinmetz's formula, the heat energy due to hysteresis is given by

, and,

hysteresis loss is thus given by

where, f is the frequency, η is the hysteresis coefficient and βmax is the maximum flux density, the empirical exponent of which varies from about 1.4 to 1 .8 but is often given as 1.6 for iron.[40][41][42]

— Preceding unsigned comment added by 69.39.242.99 (talk) 18:49, 2 January 2015 (UTC)

Steve: thanks for taking the time to write about the problem. Maybe the article was vandalized while you looked at it or the images failed to load in your browser; the formulas show to me and they're fine (I use Iceweasel under a fully free software GNU/Linux system). I have put your comment in a section of its own and deleted the leading whitespaces in your comment because they cause a spurious formatting. Mario Castelán Castro (talk) 03:05, 13 February 2015 (UTC).

Also[edit]

Re. the ungrammatical use of "also", I put the wrong link in my edit comment it should be Talk:Electromagnetic induction#Also. Sorry about that. — Cheers, Steelpillow (Talk) 10:08, 16 March 2015 (UTC)