I have a goofy question and I can't find my old college physics books.. :(
When two identical repelling electromagnets are brought close together, does the DC current change?
Details
Q2: Do different levels of DC across a toroid inductor affect the ESR? (Assume no wire heating effects..) D from BC
The current changes transiently as they are brought together... increases I think. Then it decays exponentially back to the original steady-state value, E/R. So it depends on your definition of "DC."
Depends on your definition of ESR, but if you mean AC impedance, for a ferrous core, yes. For an air core, no.
John
Lense's law implies an increase.
I think there is a small increse in the DC resistance too. It is unlikely that you will ever see it in a real situation but perhaps at some extreme it will show up. The electrons flowing in the copper will have their paths deflected slightly by the field.
Seeing as it's you, (and not another homework question) I won't take it literally.
If I can also ignore any magnetostrictive effects and only measure the steady state (and not what happens immediately after the magnets stop moving) the answer is no.
no, but it can effect inductance if it's saturable.
Bye. Jasen
Yeah...I know its a homeworky type question... :)
I didn't think static magnetic fields significantly affect wire current density but wasn't sure... (Ex..permanent magnet resting on a wire. )
For example... I"ve never heard if wire conducts more (or less) at the north pole. (neglecting temperature effects ) Could be the start of another speaker wire myth... Better sound at the North pole... :)
D from BC
I suppose that happens in a straight conductor in free space too, a sort of spiral electron path due to Hall effect. So Mr Ohm was wrong after all!
Gosh.
John
There would be a Hall potential developed in the wire at certain magnetic field orientations, and that could increase resistance slightly. I don't know if it's enough to measure, probably not.
Yup, Hall Effect Harmonic Distortion. You heard it here first.
John
lol :) D from BC
What you mean is the Lorentz force which in turn causes the Hall effect.
robert
Great. Another market for my cow magnet business. The gas mileage boost scam was getting a bit old.
-- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ Personally, I\'m against people who give vent to their loquacity by extraneous bombastic circumlocution.
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