Four Key Indicators for Understanding a Magnet
- Br (Remanence · Residual Flux Density) : the magnetic flux remaining after the external field is removed. Higher Br = stronger magnet.
- Hcj (Intrinsic Coercivity) : the reverse field strength that a magnet can withstand without losing its magnetization. Critical in high-temperature or high-load environments.
- BHmax (Maximum Energy Product) : the maximum energy density the magnet can deliver — an overall performance indicator.
- Temperature Coefficient : the decay rate of Br and Hcj with temperature change. Lower is better for thermal stability.
For demanding applications such as EV traction motors, where both temperature and load are high, Nd magnets with high Hcj (SH / UH / EH grades) are typically selected.