BHMag Database

BHmag database is a compilation of ~ 300 digital B-H Curves of almost all known soft magnetic materials.  The database covers a broad range of permeability from  10 to 10,000.  High permeability magnetic materials such as Electrical Steel, Metglas are mostly available as thin lamination sheet. Medium permeability materials such as mild steel, stainless steel and casting are available as machinable bulk solids such as round, wire, bar, slab or plate.  Low permeability materials such as powder cores are available as  nonmachinable solids.   BHmag database presents magnetic properties of  all these materials.  So it is useful in the design of diverse electrical equipment such as MRI. HEV, maglev, wind generators, electric motors, transformers, solenoids, inductors, relays etc.

BHmag’s database is an electronic file which contains the Magnetization curve, Permeability curve, Saturation induction and Electrical conductivity of magnetic materials.   It presents the B-H curve in normalized SI units.  It also contains useful information such as manufacturer,  thickness and frequency at which the magnetization curve is measured as well as annealing condition of magnetic materials. Each electronic files contains one digital  B-H curve.  Each file stores a large number of data point (B, H, mur) to preserve nonlinearity inherent in the B-H and mur-H curves.  

1.1          Database Folders

The BHmag database is actually an electronic folder with the same name on a server. It contains 11 subfolders. Each folder contains several B-H excel files in a specific material category as given in Table 1. Each excel file contains one specific digitial B-H Curve.

Table 1.  Folders in the BHmag  Database


Symbol Folder Name Nr. of Excel Files
A Electrical Steel NGO 96
B Electrical Steel GO 37
C Metglas & Nano 11
D Cobalt Steel 15
E Nickel Steel 37
F Stainless Steel 16
G Low Carbon Steel 25
H Castings 15
I Iron Powder Core 14
J Alloy Powder Core 27
K Ferrite Powder Core 7
Total Nr. of Digital B-H Curves (data files) 300

– 196 of these digital B-H curves define “electrical steels”.  They are thin laminations with high relative permeability, ranging 1000 to 10000.  They are subdivided into 133 for Silicon Steels, 11 for Metglas and Nanocrystalline materials and 15 for Cobalt Steels and 37 for Nickel Steels.

– 56 of these digital B-H curves define “industrial steels”.  They are bulk solids such as plates, rounds with medium permeability ranging 500 to 2000. They are subdivided into 16 for Stainless Steels, 25 for Low Carbon Steels and 15 for Castings.

– 48 of these digital B-H curves define “powder cores” . They are specific 3D shapes such as torids, pot core etc, with low permeability ranging 10 to 500.  They are subdivided into 14 for Iron Powder Cores and 29 for Alloy Powder Cores and 5 for ferrite cores.

Thus the BHmag database presents Magnetization and Permeability curves for a wide range of magnetic materials.   So it is useful in the design of broad range of electrical equipment such as electric motors, generators, transformers, solenoids, inductors, relays etc.

The user can easily integrate the database into any commercial Magnetic Field Software. Such integration relieves the designer the burden of selecting a trial magnetic material, collecting B-H curves, normalizing them into standard units, digitizing them and manually entering the data into the software, designing the electric machine and repeating the tedious process with another material. A magnetic field software with built-in BHmag database can be used to quickly run the “what-if” simulations to analyze how change of materials affects the performance of machines. With few clicks, the designer can change a magnetic material and evaluate the impact of changed material on the performance.  Such fast what-if simulations greatly reduce the time for selection of optimal magnetic materials, significantly reducing the design cycle time.

1.2          Index

The BHmag database also contains an excel file named BHmag Index that lists key material information of the BH curves.  This index file contains more information on each magnetic material.  These include the manufacturer, brand name, thickness, annealing, and the saturation flux density Bsat plus electrical conductivity. The index is supplied free when the digital curves are purchased on-line

1.3 User Manual

BHMag database is supplied with a comprehensive User Manual when the digital curves are purchased online. The user manual contains more detailed information on the database format, magnetic saturation and quality of digitization and other useful information.