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How can I compare the second quandrant of a permanent magnet's B-H curve with the operating point of a permanent magnet in the magnetic circuit?

How can I compare the second quandrant of a permanent magnet's B-H curve with the operating point of a permanent magnet in the magnetic circuit, relative to that B-H curve?

Given a certain grade of permanent magnet, for instance N42UH, the B_rem and H_c are known values, and the second quadrant of the magnetisation curve can easily be drawn.

Now, let's consider the permanent magnet in a magnetic circuit (C-core with one airgap). I want to determine the operating point of the permanent magnet relative to the B-H curve, this is called the load line, or operating point, normally indicated by B_m and H_m.

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Flux

v2021.1

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Mohammed Elamin_22169

Hi jvdam42,

you can plot the magnetic Flux density on the magnet after solving (Graphic>>isovalues>>new) and visually look at values. I think for C core you will typically see constant value across the magnet.

or you can also create a sensor (Advanced >>Sensor>>new) in the postprocessing and look at the B in specific location in the magnet or the average over the magnet.

I hope this helps,

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jvdam42

Thank you for your reply. I am familiar with what you describe, however, it is not what I am looking for.

The picture below shows the second quadrant of the B-H curve, where the permanent magnet's demagnetisation curve is shown between Br and -Hc, while the operating point of the permanent magnet in the magnetic circuit is indicated by (Hm,Bm). The line between (0,0) and the operating point (Hm,Bm) is the load line, and it is a measure for how effective the permanent magnet is being used in the circuit, and how high the magnetic loading is.

My question is, how can I determine Hm and Bm for a permanent magnet that is used in a circuit using FLUX?

jvdam42

@Abdesssamed soualmi, @Farid zidat, could either of you please try to help me out here?

In addition to my questions above, I am trying to understand why in FLUX it is chosen to have the magnetic field, H, and the magnetic flux density, B, in the same direction in a permanent magnet, while in fact, they are in opposing directions in a magnet. Could you elaborate here?

Also, could you explain how permanent magnets are implemented in FLUX? Are they used as equivalent current sources, or is the equivalent MMF used directly, or another method?

SimonGuicheteau

The results you get at the end should be the actual H or B field in the magnet. If you want to see the H field along the magnet orientation you can plot something like H*Br/Mod(Br). A negative value here would mean that you are on the second quadrant