Based on a finite element model of three-dimensional moving eddy current field, the electromagnetic field distributions of permanent magnet eddy current coupling are analyzed and the power and torque transferred between motor shaft and load shaft are calculated. Using this model, the influences of main dimensions of the permanent magnets (PM) and copper discs on the characteristics of permanent magnet eddy current coupling are numerically investigated. The primary optimal design project of permanent magnet eddy current coupling is obtained. The ratio of PM can be determined to be about 0.7. The appropriate thickness of PM should be chosen according to the inflexion of the relationship curve between the output power and the thickness of PM. When determining the number of pole pairs, different ratios of PM should be taken into account to ensure that the ratio of the arc length at the position of fan-shaped PM average radius to the radial width of PM is within the corresponding range. The thickness of copper discs should be chosen from 6 to 9 mm. The inner and outer radii of copper discs should be determined by the condition that the ratio of the radial width of cooper plate to the radial width of PM ranges from 1.2 to 1.6. An experiment system is tested to validate the correctness of the model and numerical analysis.
