Permanent magnetic materials: permanent magnetic material by the external magnetic magnetic disappear, can provide stable magnetic field on the outer space. Neodymium iron boron permanent magnet commonly used measure of the following four ways: the remanent magnetization (Br) unit for the Tesla (T) and Gauss (Gs 1Gs =0.0001T) will be a magnet in the closed environment is the external magnetic field magnetized to saturation after the withdrawal of the technology of external magnetic field, magnetic induction intensity at the magnet performance we called remanence. It indicates that the magnet can provide maximum flux value. Visible from the demagnetization curve, which corresponds to the air gap is zero, so the magnetic circuit of magnetic induction intensity of the magnet are smaller than the remanence. Neodymium iron boron is now found in the highest utility Br permanent magnetic material. Magnetic coercivity (Hcb) unit is the an / M (A/m) and OE (Oe) or 1 Oe = 79.6A/m in the saturation magnetization of the magnet in technology after is reversed when magnetizing, so that the magnetic induction intensity reduced to zero required reverse magnetic field strength value is called magnetic coercivity (Hcb). But this magnet magnetization is not zero, just cancel each other out magnetization effects of reverse magnetic field and magnet and the. (external magnetic induction intensity is zero) if the withdrawal of external magnetic field, the magnet is still has certain magnetic properties. Neodymium iron boron coercive force is generally more than 11000Oe. The intrinsic coercivity (Hcj) unit is the an / M (A/m) and OE (Oe) 1 Oe = 79.6A/m so that the magnetization magnet for magnetic field intensity drop reverse zero required applied, we call the intrinsic coercivity. Intrinsic coercive force is a physical quantity to measure the magnet resistance to demagnetization, if the applied magnetic field is equal to the intrinsic coercivity magnets, magnetic will be basically eliminated. Neodymium iron boron Hcj will reduce with the increase of temperature and so need to work in a high temperature environment should choose high Hcj grades. Magnetic energy product (BH) unit for kJ / M 3 (J/m3) or high - Austria (GOe) 1 MGOe ~ 7 96k J/m3 product of demagnetization curve on any point of the B and H both BH we called magnetic energy product, and B * H and the maximum value is called the maximum magnetic energy product (BH) max. Magnetic energy product is one of the important parameters of the energy stored in the magnet size constant, (BH) max greater the magnetic energy magnet contains more. Design of magnetic circuit possible to make magnet operating point is near the maximum magnetic energy product of the B and H.
Isotropic magnet: magnet magnetic properties are the same in any direction. Anisotropic magnets: the different direction magnetic properties will be different; and there is a direction, in the direction of orientation when the highest magnetic properties of magnets. Sintered NdFeB permanent magnet is anisotropic magnet.
Orientation: anisotropic magnet can obtain optimal magnetic properties is called the orientation direction of the magnet. Also known as "the axis of orientation", "easy axis of magnetization".
The magnetic field strength: refers to the space somewhere in the magnitude of the magnetic field, denoted H, its unit is an / M (A/m). Magnetization: refers to the material inside the unit volume of magnetic moment vector and, with M said, the unit is an / M (A/m). Magnetic induction intensity: the definition of the magnetic induction intensity of B is: B= 0 (H+M), where H and M are respectively the magnetization and magnetic field strength, and Mu 0 is the permeability of vacuum. Magnetic induction intensity is also known as magnetic flux density, magnetic flux per unit area of. The unit is the Tesla (T). Flux: the total magnetic induction intensity in a given area. When the magnetic induction intensity B uniform distribution on the surface of A magnet, the general formula of flux for =B in diameter and A. Flux unit SI is Maxwell.
Relative permeability: media permeability relative to the vacuum permeability, i.e. r = mu / O. In the CGS unit system, o=1. In addition, the relative permeability of air in actual use tend to value to 1, in addition to the relative permeability of copper, aluminum and stainless steel material is also approximately 1.
Magnetic flux and magnetic motive force: the ratio of F, the conductance is similar to the circuit in the. Is a reflection of a physical quantity materials magnetic capability. Magnetic conductance coefficient Pc: for the demagnetizing factor, in the demagnetization curve, ratio of the magnetic induction intensity Bd and the magnetic intensity of Hd, namely Pc =Bd/Hd, magnetic conductance coefficient can be used to estimate the value of the flux under various conditions. For isolated magnet Pc only related with the magnet size, demagnetization curve and Pc line intersection is magnet operating point, larger Pc magnet operating point is higher, the more difficult to demagnetization. The general case for a solitary magnet orientation relative larger Pc larger length. So Pc is an important physical quantity in the permanent magnetic circuit design. |
