Eddy-current coupling with slotted conductor disk

Eddy-current couplings are becoming popular devices for speed and torque control. Efficiency of these couplings depends on the excitation level; therefore, the routes and density of induced currents affect it significantly. This paper focuses on the design of a squirrel cage-type coupling disk, which forces eddy currents to flow perpendicular to both magnetic field lines and the axis of rotation. Lorentz force and transmitted torque are consequently optimized. The investigation is performed both numerically and experimentally, with results being presented for variable air gaps and speeds. A comparison between plain and slotted disk conductors, tested under identical set-ups, demonstrates the effect of the proposed design on torque throughput and efficiency. In addition to this, the influence of number and size of slots and the effect of filling slots with iron are studied by parametric finite-element modeling verified by experiments.