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Does back E.M.F. also generate a back E.M.F. of it's own?

If so, why do I not hear this discussed? Is this because it has a very small effect, i.e. it lasts a small amount of time or it has a small magnitude.

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marked as duplicate by John Rennie electromagnetism Apr 6 at 9:59

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  • $\begingroup$ Would an explanation in the context of a simple LR circuit be sufficient? $\endgroup$ – Aaron Stevens Apr 5 at 19:11
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    $\begingroup$ IMO, the concept of "back EMF" only makes it harder to understand inductors and electrical machines. Take an ideal inductor, for example: The current through it and the voltage across it are related to time by, $v=L\frac{di}{dt}$. That equation is always true. There's no "back EMF" in it, but it can tell you all that you need to know. It seems to me as if, "Back EMF" is a story that instructors tell to students when they are not yet ready to teach the math. $\endgroup$ – Solomon Slow Apr 5 at 20:06
  • $\begingroup$ Very closely related: physics.stackexchange.com/questions/400272/… $\endgroup$ – PiKindOfGuy Apr 6 at 2:29
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Back EMF is computed on the basis of a magnetic flux and area; the same area, and the same flux, doesn't generate a 'second' effect. The importance of the back EMF in the operation of motors and transformers is in conservation of energy: any motor power not taken up by the load, results in lessening the input energy delivered, because an unloaded motor generates higher back-EMF than one which is doing work.

Effects of the back-EMF in a motor DO happen back at the powerhouse in the generator there, where less energy is required to turn it, but that is a different magnetic field, and a different area, and not generally a user concern. Other effects of the back-EMF in a motor are seen in the power meter for my house, of course: I find that quite gratifying.

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