Two magnets may have the same shape, dimensions and even look identical.
Yet once installed in the same application, they can deliver completely different performance.
The reason is not always the magnet grade (N35, N42, N52...), but three key parameters found on every magnet datasheet: Br, Hcj and BHmax.
Understanding these values helps engineers select the right material, avoid oversizing and prevent performance issues during operation.
Br (Residual Induction)
Br (Residual Induction) represents the magnetic induction remaining in the material after magnetization.
In practical terms, it describes the magnetic flux available on the magnet surface (expressed in Tesla or Gauss).
A higher Br generally means a stronger magnetic field and higher performance for the same magnet geometry.
Hcj (Intrinsic Coercivity)
Hcj measures the magnet's resistance to demagnetization and magnetization reversal.
It becomes particularly important when magnets operate:
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at elevated temperatures;
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in opposing magnetic fields;
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inside electric motors, actuators and dynamic systems.
A magnet with high Br but insufficient Hcj may initially perform well but become unsuitable under demanding operating conditions.
BHmax (Maximum Energy Product)
BHmax represents the maximum magnetic energy stored per unit volume.
Simply put, it defines the magnetic power density of the material.
Higher BHmax values often allow engineers to design smaller, lighter and more compact magnetic assemblies while maintaining the required performance.
The Most Common Mistake
One of the most common mistakes is selecting a magnet based solely on its commercial grade (N35, N42, N52...) without evaluating Br, Hcj and BHmax.
The correct material should always be chosen considering operating temperature, geometry, magnetic circuit and real working conditions.
For example, an N42SH magnet may be a far better solution than a standard N52 when the application operates at elevated temperatures.
A Datasheet Tells Much More Than the Magnet Grade
Br, Hcj and BHmax are not just technical abbreviations.
They define how a magnet will actually perform inside your application.
Understanding them means making better engineering decisions, improving reliability and avoiding costly design mistakes.
If you need support interpreting a magnet datasheet or selecting the most suitable material, our engineering team will be happy to assist.