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Talk:Magnetic inductance

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February 2015

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"You have completely misunderstood this article." Okay - so what is this article about? If I don't understand the difference between this topic and inductance, I suggest it needs more context. This is a general encyclopedia, (among other things) and it would confuse J. Random User if he typed in this article title expecting to read about inductance - I certainly find it bewildering and frightening. Abstruse principles of circuit theory ought to be properly sequestered in the depths of the temple, lest us common folk inadvertently profane them. --Wtshymanski (talk) 18:37, 12 February 2015 (UTC)[reply]

The article is not about inductance but the analogy of inductance in a magnetic circuit. It is not the same as inductance, just as reluctance is not the same as electrical resistance. One can see this from the dimensions cited for magnetic inductance (seconds/ohm, or amp-seconds/volt) whereas the dimensions of actual inductance are volt-seconds/amp. This is the result of making mmf the analog of emf and time rate of change of magnetic flux the analog of electrical current. I fully agree with you that this is far from clear in the article, but hey, I had nothing to do with writing it, or its parent article gyrator-capacitor model. SpinningSpark 23:15, 12 February 2015 (UTC)[reply]
I'm going to paraphrase that and stick it in the lead to warn the unwary such as myself. It would also be nice if someone explained why someone would use a gyrator-capacitor model and where this would be preferable to a balsa-wood model. Context is key. Do we have magnetic circuit? Oh good, it's blue. --Wtshymanski (talk) 15:15, 13 February 2015 (UTC)[reply]
It's good to give the motivation for some modeling scheme - the encyclopedia reader doesn't have our motivation of passing the exam at the end of the term, when reading our typed-in class notes. --Wtshymanski (talk) 15:21, 13 February 2015 (UTC)[reply]
This is the third article in as many days that Wtshymanski has found that discusses a subject that he does not understand ("I don't understand the difference between this topic and inductance") and all of them he has described as someone's 'course (or class) notes'. He has also deleted and redirected or PRODed each and every one. After all, if Wtshymanski does not understand it, it is clearly made up and does not belong in an encyclopedia does it? DieSwartzPunkt (talk) 16:19, 13 February 2015 (UTC)[reply]
Thank you for edit conflicting me. Now that we have got the insults and bitch-slapping out of the way perhaps you will allow me to continue discussing the actual article. SpinningSpark 17:02, 13 February 2015 (UTC)[reply]
The basic reason for using this model is that its circuit diagram can be directly connected to the actual electrical part of the system and analysed as a unified whole as an electrical circuit. The standard analogy for magnetic circuits does not work in this respect. In that model the effort variable is mmf (analogous to emf) and the flow variable is magnetic flux (analogous to current). The ratio of the two is reluctance, analogous to electrical resistance. However, an ideal reluctance does not dissipate any heat so the model does not work from an energy flow point of view. To get it to work one must choose a pair of variables to be analogs of I and V that are power conjugate variables. I recently wrote an article Mechanical-electrical analogies which covers the equivalent problem for mechanical systems.
I agree that the article, along with several others like magnetic capacitance, would be better described in a single article for the model. Another recent article of mine, Impedance analogy, could serve as a template. In answer to your edit summary comment, there are plenty of English language sources on Gscholar. The ref in the gyrator-capacitor model is viewable online. The paper is by David Hamill who seems to have invented the term in the 1990s. However, I'm not so certain that Hamill actually invented the model. The idea that conjugate pairs are needed when models traverse energy domains has been known at least back to the 1930s, maybe earlier, and theories were developed that can model anything, regardless of domain. Possibly the novel thing that Hamill brings to the table is he introduces electrical engineers to the idea that a gyrator is required (in the circuit model) to interface between the electrical and magnetic domains. While that may be an unfamiliar concept to electrical engineers, I suspect that to control system engineers it is just routine procedure. Anyway, there seems to be plenty of other people worldwide using Hamill's terminology so I don't think there is going to be anything undue in using his names and references. SpinningSpark 17:02, 13 February 2015 (UTC)[reply]