The eddy-current analysis and transmit-torque calculation for the permanent eddy-current coupling based on the equivalent-depth method

The structure and working principle of the permanent eddy-current coupling are introduced. The depth of penetration is involved and the expressions of the eddy-current density are derived according to the electromagnetic field theory. Formulas of transmit-torque calculation of the permanent magnetic coupling are derived from the eddy-current expressions with converting the demagnetizing effect of the eddy-current to the permanent magnet. The expressions shows that the calculating parameters correlate to each other, the result of theoretical calculation generally agrees with the experimental values, and the proposed method is feasible and can be used to the design and development of the permanent magnetic coupling.