Questions tagged [magnetics]

Important to inductors, transformers, generators, motors, magnetic fields, inductive heating, magnetic storage, permanent magnets

A changing electrical field produces a magnetic field. These magnetic fields can be used to store and transfer energy, as in an inductor or transformer. Proper mechanical application of the generated magnetic field can apply force or torque to create motion, as in a motor. Reverse application of the same principle can use mechanical action to generate electricity, as in a generator. Information can be stored in magnetic domains, as in a hard disk or magnetic tape.

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Finger magnets and MRI

A few years ago in the biohacking community there was a phase where people (mostly engineers) were having small magnets embedded in a fingertip in order to sense magnetic fields. I was slightly tempted at the time but never had the procedure. Since…
Dirk Bruere
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Why is the magnetic field inside a coaxial cable the same as it would be near a current-carrying wire?

Why is the magnetic field inside a coaxial cable the same as it would be near a current-carrying wire? Each side of the cable is conducting so shouldn't it be \$ \frac{I*μ0}{\pi*r} \$ because both sides contribute equally (at least in the middle…
CapBul
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Magnetic field in the air gap of a transformer core

I am trying to calculate the magnetic field, Hg, and have been looking these formulas. I would like to know if I am on the right track, as something is not working out for me. From these with a uniform area, the area of the core, Ac is equal to the…
Dave
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Reducing the field of a magnet?

We have an existing magnet (SmCo) that needs to be less powerful. Is there any way of doing this without altering its dimensions? I can imagine filing bits off it, adding spacers etc, but these are not options. One suggestion is to partially…
Dirk Bruere
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What does a 2D Halbach array look like?

A 1D Halbach array looks like the below: What would it look like in 2D, in order to make a square array?
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Loopy Artifacts in B-H Curves

Does anyone know the term for these artifacts in a B-H curve and their cause? I have no idea what to use to look up anything about them. These were obtained from the terminals of running a generator with various, sometimes switched, loads, and…
DKNguyen
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why cannot use permanent magnets for large electricity production

Why cannot use permanent magnets for large electricity generation as they donot require power to produce strong magnneticfield
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How to create rotating magnetic field using four electromagnets

How would you create a rotating magnetic field using 4 big electromagnets located equal distance around the DUT. The magnets are configured in pairs of two (magnets opposite each other), controlled by bipolar PSUs (2) in Constant current mode (the…
super7800
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How to solve magnetic circuits with windings in series?

Given the circuit in Figure 1, how would one go about finding V_EF? For me it is clear that V_AB + V_DC = 200 and that the current through windings AB and CD is the same. In addition, Φ_1 = Φ_2 + Φ_3. The approximation of the sum of magnetomotive…
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Positioning of Air Gap in a Magnetic Core

We are making a rotating machine where we need to measure the flux in the air gap, however, the flux sensor is too thick to fit in the airgap so a slot will need to be cut into the face of the pole so the flux sensor can slide into it. But before we…
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How strong is the field of a magnetic strip on a credit card?

How strong is the field of a magnetic strip on a credit card? In other words, at the typical distance of a read head, say 0.001" how strong is the magnetic field from the stripe? (Note this is NOT a question about how strong a field is needed to…
Tyler Durden
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Is there a way to make an experimental magnetic head?

I recently had a magnetic stripe on my bank card fail and I was curious to find out the exact nature of the corruption which would require scanning the surface of the stripe and determining its magnetic characteristics. I was wondering if there is…
Tyler Durden
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Why would running the coil cable straight for ~10 inches affect metal detector sensitivity?

Metal detecting enthusiast here. I have been reading various posts pertaining to sensitivity of metal detectors. It is has been suggested that instead of immediately wrapping the coil cable around the stem to instead run the cable straight up the…
Anton
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Calculating the mean path length of a core

I have the following magnetic circuit problem: For the left hand core, the mean path length calculated in the solution manual is 1.11m. However what I don't understand is, why is the length of the air gap included? Don't you have to subtract the…
hacker804
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Will plastic influence a magnetic field?

First of all sorry for my English. If, for example I will "create" magnet by passing current through a coil. And than I will "wrap" this piece with plastic or some other material, will the "magnet power" (not really power..) And by "magnet lower" I…
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