What are the differences between the magnetic circuit and the physical characteristics of the strong magnet

The main differences between magnetic circuit and circuit physical properties are as follows:
(1) There are good conductive materials in nature, and there are also materials that insulate current. For example, the resistivity of copper is 1.69 × 10-2qmm2 /m, while that of rubber is about 10 times that. But until now, no material has been found to insulate magnetic flux. Bismuth has the lowest permeability, which is 0. 99982μ. The permeability of air is 1.000038 μ. Thus air can be regarded as the material with the lowest permeability. The best ferromagnetic materials have relative permeability of about 10 to the sixth power.

(2) Current is actually the flow of charged particles in the conductor. Due to the existence of conductor resistance, the electric force does work on charged particles and consumes energy, and the power loss is converted into heat energy. The magnetic flux does not represent the movement of any particle, nor does it represent the loss of power, so this analogy is not necessary. The electric circuit and the magnetic circuit are quite separate, each with its own inner bundle. Loss, so the analogy is lame. The circuit and the magnetic circuit are mutually exclusive, each with its own unquestioned physical connotation.

Magnetic circuits are looser:
(1) There will be no circuit break in the magnetic circuit, magnetic flux is everywhere.
(3) Magnetic circuits are almost always nonlinear. Ferromagnetic material reluctance is nonlinear, air gap reluctance is linear. The magnetic circuit ohm’s law and reluctance concepts listed above are true only in the linear range. Therefore, in practical design, b-H curve is usually used to calculate the working point.
(2) Since there is no absolutely non-magnetic material, the magnetic flux is unconstrained. Only part of the magnetic flux flows through the specified magnetic circuit, and the rest is scattered in the space around the magnetic circuit, which is called magnetic leakage. Accurate calculation and measurement of this magnetic flux leakage are difficult, but cannot be ignored.


Post time: Mar-07-2022