Field computation and irreversible demagnetisation loss for cylindrical permanent magnets stabilised in air

A new finite element formulation for solving the axisymmetric field of cylindrical magnets stabilised in air is presented in the paper. Experimental verification indicates good agreement with the field computation method. By using the method, the amount and distribution of irreversible demagnetisation loss within the air-stabilised cylindrical magnets can be accurately determined. Design curves for rapid predicting the irreversible demagnetisation loss are given. The effects of magnet material and geometry parameters are discussed.