A large cylindrical neodimium magnet or stack of same, with a coil wound around it. In an unpowered state the magnet would have a certain attraction. With one polarity of current, I would imagine the coil would amplify the permanent magnet field/attraction. With the reverse it would decrease the attraction, potentially neutralise or invert it. Is this feasible or likely to damage the permanent magnet?

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Wischarm1q · Accepted Answer

When a magnet is first manufactured, it has no overall magnetism. To make a permanent magnet it has to be magnetized. This is done by putting a coil round it and applying a large pulse of DC current.Generally speaking, it will remain magnetized until a strong enough pulse is applied in the opposite direction.If you apply enough reverse current to cancel out the permanent field, it will be similar in magnitude to the current used to create the magnet and will flip the magnet across too.The usual way to demagnetize or &quot;degauss&quot; an object is to apply an alternating current and slowly decrease its intensity to zero so that each peak magnetizes the material less and less. Another way can be to temporarily heat the material above its Curie point. But either way, you would have to re-magnetize it before switching off.

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