one: English reply: Return Magnetic Permeability: permeability of the demagnetization curve: Demagnetization Curve
Two: initial permeability: permeability along with the change of magnetic field strength, magnetic field intensity at zero when the permeability is nonlinear, and smaller, a later value over the strength of the magnetic field, magnetic permeability will be significantly larger, and in a range of basic invariant. Permeability in becomes larger and later in a scope basically unchanged before called initial permeability permeability. The demagnetization curve: magnetic alloy hysteresis loop second or fourth quadrant that part of the curve. Generally refers to the use of a monotonic variation of the magnetic field from the saturated demagnetization situation. Three: when the magnet under dynamic conditions, internal and external reverse magnetic field demagnetizing field Hd H or a magnet to a periodic variation, the operating point of D at this point as shown in Figure 2 is cyclic variation, defined in B magnet demagnetization curve work point on the D reciprocating change trajectory for the back line of the magnet dynamic, slope of this line as the reply to permeability of rec.. Obviously, the reply permeability rec. characterization of stability of magnets in the dynamic operating conditions, it is also the permanent magnet B demagnetization curve square degree, so it is one of an important indicator of the magnetic properties of permanent magnet. For sintered Nd-Fe-B magnet demagnetization curve is a straight line, B and bHc approximately equal to Br, the return permeability Mu rec. equal to B of the demagnetization curve slope and rec.=1.03~1.10. Rec is small, the stability of the magnet in the dynamic working conditions is better.
It is worth noting that if the B curve is not linear demagnetization magnets, magnet permeability rec. is back at different operating points have different values, how to put the design of magnet in the most stable working state, it is very important to.
Four: curve J defined magnet demagnetization, reverse magnetic field size when J=0.9Jr is Hk, Hk/jHc can be expressed intuitively magnet demagnetization curve of J square. For sintered Nd-Fe-B magnets with high jHc, jHc is far greater than the bHc, when the reverse magnetic field more than bHc but less than jHc, the corresponding B demagnetization curve has entered the third quadrant. By (1-1) shows that, if the curve J demagnetization magnet is still a straight line, the corresponding third quadrant B demagnetization curve also keep in line, this magnet? Rec remained a small value, the reverse of external magnetic field is removed, the magnet operating point can still be restored to its original position. Therefore, one of the important indexes of the magnetic properties of Hk/jHc are permanent magnet, it and rec, characterization of stability of magnets in the dynamic working conditions. Permeability, also known as magnetic conduction coefficient is a coefficient of magnetic properties measurement of material, with the letter Mu said that the unit is H / m. |
