TEFC Motor Thermal Protection System Based on a Two-channel Thermodynamic Model

An approach to the construction of an induction motor thermal protection system based on the separation of thermodynamic processes into fast and slow processes is presented. The structure is substantiated and a mathematical description of a two-channel thermodynamic model is obtained, in which this approach is implemented. The advantage of the proposed approach is the small amount of initial data required to parameterize the thermal protection system. Also, the proposed version of the thermal protection system provides a simpler solution to the problem of setting the initial conditions for starting the protection system after an interruption than systems for monitoring the thermal state of an electric motor using traditional thermal models. An approach to taking into account the effect of speed changes on motor cooling is presented. The algorithm of operation of the thermal protection system based on a two-channel model is described. The results of modeling this protection system are presented.