Timeline for Using a permanent magnet as an electromagnet core
Current License: CC BY-SA 4.0
5 events
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| May 13, 2021 at 18:44 | comment | added | Guy Inchbald | @JCollins No, it doesn't work like that. This is the third time of saying, how many more must I say it; you need the long pulse train to demagnetize. You should be asking why it is that way, not suggesting it is wrong. It is in fact because of something called magnetic hysteresis, see en.wikipedia.org/wiki/Magnetic_hysteresis . I think you really need to understand the physics a bit better. | |
| May 13, 2021 at 17:13 | comment | added | J Collins | Pulse comes from your first paragraph, and makes the assumption that a well quantified single pulse could have the same effect on a known magnet as a degaussing wave on a less well defined magnet. Would you say that the magnetic field required to demagnetise a cold magnet would be similar in magnitude to that required to re-magnetise the same cold magnet? Correct, I am not thinking of a heating system. Regarding tri-state, I am looking to use two of the three states, magnetised in one direction or demagnetised. | |
| May 13, 2021 at 17:04 | comment | added | Guy Inchbald | @JCollins "On-off" is a bad way to talk about magnets, they are essentially tri-state: one direction, demagnetized, or the other direction. As I said, to demagnetize one you need a gently decaying train of alternating pulses. I am not sure how you got "a pulse" from that. Heating to the Curie temperature will destroy any existing magnetism, cooling in the presence of an external magnetic field will re-magnetize it that way; it's how rocks get magnetized. But I assumed you had no such oven-baked solution in mind. | |
| May 13, 2021 at 16:16 | comment | added | J Collins | Does this suggest a neodimium magnet could be used and it essentially be permanently switched with a pulse of field inducing current to either switch it permanently on or off? This seems to present a very interesting opportunity if true. I was under the impression the metal needed to be heated for the field to change, either align or misalign. | |
| May 12, 2021 at 13:04 | history | answered | Guy Inchbald | CC BY-SA 4.0 |