Analysis and Simulation of Thermodynamic Processes in High-powered AC Electric Motors

Proposed analytical expressions are based on a three-stage heating theory, which allow an approximate estimate of the average temperature of the stator winding in high-powered electric motors. It is shown that the numbers of motor temperature sensors commonly used in action of an electric drive are not enough for a complete analysis of the temperature state of the stator winding. To build a system for monitoring the thermal state of an electric motor, the simulation is required which is based on the method of thermal circuits. This approach allows to take into account the temperature distribution along the winding and other features of heating in an electric motor. Thermodynamic models in combination with the insulation state monitoring based on the registration of capacitive leakage currents make it possible to estimate the residual insulation life of the winding and to forecast its estimated service life.