Prediction of ultimate coupling torque during transient short-circuit loads of electric motors

Abstract

The power of electric motors is transmitted by mechanical drive train. The dimensions of train components are determined by steady-state and transient loads. Usually, the dimensioning torque is the electric short-circuit load. Thus, the prediction of these loads is needed in early phase of any actual project. This is challenging because the components are produced by separate manufacturers. In addition, the encountered component loads are dependent on the vibration characteristics of the torsional system. The aim of this paper is to review the main parameters affecting the ultimate coupling torque. A simple torsional model is applied for the demonstration. The main parameters of the system are the natural frequencies of the lowest modes and the inertia ratio between the motor and the driven system. Finally, the findings are compared to the standard requirements and a novel dimensioning approach is presented.