This article presents the analysis of the three-dimensional forces applied by a slotless Lorentz-type fully-active magnetic bearing actuator. An analytical model is presented for defining the forces applied by every radial and axial bearing of the actuator, which allows identifying cross-couplings and deviations from the ideal forces, an essential step for their minimisation. A validation campaign is performed to guarantee and assess the accuracy of such a model employing a magnetic bearing demonstrator that features a dual hetero/hompolar machine design.