reversible flux loss, irreversible flux loss of rare earth permanent magnets

Permanent Magnet Maximum Working Temperature

Permanent magnets are widely applied in various motors, sensors/instruments and electronics, their temperatures almost vary more or less during work. These temperature variations are resulted from eddy current effect and/or ambient temperature variation. Due to thermal fluctuation and magnetic domain evolution, a permanent magnet loses some or all magnetic flux when its temperature elevates. Here comes a question, how high temperature can a permanent magnet withstand to work? For a commercial permanent magnet, the upper temperature limit is called maximum… Read More

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N48SH Grade Neodymium Magnet Demagnetization Curves

What are Permanent Magnets Temperature Coefficients α and β?

A permanent magnet’s magnetic properties change as a variation of temperature. For a permanent magnet, remanence (Br) and intrinsic coercivity (Hcj or Hci) are two major parameters, it is important to consider their changes with corresponding temperature variation at work. In order to describe the relative changes, they are calculated according to the following two formulas: α = [Br(T1)-Br(T2)]/Br(T1)/[ T1-T2]×100                              (1) β = [Hcj(T1)-Hcj(T2)]/Hcj(T1)/[T1-T2]×100     … Read More

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