Dynamical integrity of synchronous motion for self-synchronizing vibrating screens with two unbalanced exciting rotors

This paper investigates the robustness of self-synchronizing vibratory screens against driving torque differences between the rotors. Synchronous solutions of the mechanical system, which encompasses either a DC motor or an induction motor drive, are first obtained analytically through the averaging method, together with their linear stability properties. Then, numerical validation through direct time integrations confirmed the analytical results. The results indicate that for both motor types, there exists a parameter region, defined in terms of supplied voltages, where a stable synchronous state and a stable non-synchronous state coexist. The analysis of the dynamical integrity of the two types of motions revealed that, for both drives, in regions where synchronized motion is not globally stable, the dynamical integrity of the synchronous motion is relatively low, posing a risk to reliable operation. • Vibrating sieves have a parameter region with only locally stable synchronous motion. • Robustness decreases rapidly without the global stability of the synchronous state. • The globally stable region is larger for induction motor drives than for DC drives.