Dynamic Interaction Behavior of an Electric Motor Drive Multistage Gear Set

Abstract

For the better design and monitoring of gearboxes operating under nonstationary conditions, the dynamic interaction behavior of an electric motor drive multistage gear set is investigated in this study. Initially, dynamic mathematical models of an asynchronous motor and a multistage gear set are established by using the equivalent circuit method and the lumped parameter method, respectively. An electromechanical model coupling the asynchronous motor and the gearbox is subsequently developed, which is suitable for nonstationary conditions. The system transient responses under an impact external load are analyzed, and the mechanical torsional-vibration and electric current response are compared. Finally, the dynamic load propagation mechanism and the interaction effect on different gears are examined. The results demonstrate that the vibration frequencies of the multistage gearbox in steady and transient states both can be captured in the current. Electric current can be applied to reflect the external load variation and the internal vibration status of the driven gearbox under stationary or nonstationary conditions. The mutual excitation effects between adjacent gear pairs change the respective dynamic characteristics of the gears, and gears with small nominal loads are susceptible. INDEX TERMS Multistage gears, nonstationary operating conditions, motor current signature, electromechanical interaction, dynamic load propagation.