Home

NEWLY UPDATED!  

MagWeb is the world’s LARGEST DATABASE of Soft Magnetic Materials!

Now also has Core Loss Curves!  It has more than 1200 B-H and Core Loss Curves! 

Whether you are designing an electric motor, transformer or electric vehicle, your product is only as good as the soft magnetic materials that you employ.

Over past 100 years, engineers have developed a large number of magnetic materials to suit a wide variety of applications. But so far, selection of a right magnetic material for a specific application has been hindered by lack of a comprehensive database.  So engineers spend substantial time and effort to collect data on candidate materials for further design evaluation. MagWeb compiles the magnetic properties of all these materials (produced worldwide) into a single database. Use of MagWeb database can thus save substantial time and expense of searching for the optimal magnetic material for your product.

Magnetic Materials

Soft Magnetic materials are iron alloys which offer substantially low resistance to flow of flux than air.  They can be grouped into 12 categories listed on the left sidebar. This list spans Electrical Steel (for motors), Hiperco 50 (for aircraft generators) to Powder Cores (for inductors). Magweb is the only comprehensive database of B-H curves of all these magnetic materials produced around the world.

B-H Curve

35HX300

                        Fig. 1 Typical B-H and Permeability Curves from our MagWeb Database.

Fig. 1 shows the B-H Curve which plots the variation of Flux Density B (Tesla) with the applied Field Intensity H (A/m). It also shows the Permeability Curve, which plots the variation of Relative Permeability mur vs. H . Both are related by the fundamental constitutive equation for magnetic materials, viz. B = muo mur H .

The B-H curve has a characteristic “knee” .  Beyond the knee the permeability decreases gradually, eventually the material saturates. Below the knee, there are large number of unmagnetized domains, so a small current will be sufficient to magnetize the material – until the the permeability reaches a peak value.  Beyond this peak permeability point, fewer domains are available for magnetization.  So substantially more current will be needed to magnetize the material.   Thus, beyond the peak point, the permeability starts reducing rapidly.  As the material saturates, there will be very few unmagnetized domains. So more and more current (higher H) is required to get even slightly higher flux density B. Thus both B-H curve and the permeability curve are highly nonlinear as shown in Fig.1.

Permeability Curve

Permeability curve is more important than the B-H curve in applications that strive to use material to produce largest flux using least current.  Engineers typically are reluctant to use the material beyond a point that offers permeability that is an order of magnitude lower than the peak.   For example, for Posco’s 35HX300 NGO electrical steel has peak permeability of 9800 at 1 Tesla. The permeability reduces to about 1000 at a design point of 1.6 T.  Thus a 10-fold reduction in permeability increases the flux density only by 60%. Beyond 1.6 T, they have to apply lot more current with less and less return.

Thus peak permeability point is vital interest to identify if a designer is getting more “bang for the buck”.  MagWeb is the only database that presents the permeability curve with an identified peak permeability point.  It will also be useful in those finite element magnetic field software that rely more on the the permeability curve (or its inverse) than the B-H curve for design of electric machines.

Digitization

Computers store the continuous curves as a set of digital points. The magnetic field intensity H and permeability change by four to five orders of magnitudes range.  So choosing the number of points needed to digitizing of the magnetization curves is somewhat tricky.  On one side, representing it by too few points can result in loss of accuracy.  On the other side, using too many points can cause the B'(H) slope to oscillate, which can destabilize a FEM software.  To prevent these problems, MagWeb uses a reasonable number of equi-spaced points to digitize B(H) curve.

MagWeb Database

MagWeb  is world’s largest database of various soft magnetic materials, containing more than 1200 curves.  Each digital B-H Curve is an excel file that contains both B-H Magnetization Curve as well as Permeability Curve.   In addition, it contains hard to find metrics such as Saturation Flux Density Bs and electrical resistivity.

Thus MagWeb is a unique database of properties of software magnetic materials.  It will be useful in machines whose design centers around optimal usage of soft magnetic materials, such as all-electric vehicles, hybrid electric vehicles, Wind Generators, Electric Motors, Transformers, Inductors etc.

Share your B-H Curves

If you have B-H curves that are not available in the MagWeb database,  please email them to rao@magweb.us.  As a token of appreciation, we will send you a data folder of your choice free.