Energy-Saving Method for Predicting the Residual Life of an Electric Motor and Software Development

Energy saving and increasing the economic efficiency of electrical complexes is the most urgent task of modern energy. One of the methods of reducing power losses is reactive power compensation, both complex and local. Induction motors consume more than 60% of the electricity generated. The use of induction motors in an unregulated electric drive accounts for up to 75% of the total electric drive fleet. Every year, the emergency decommissioning of induction motors is up to 20–25%, and in some cases up to 30%. Modern microprocessor devices, which are implemented in the automation of electrical complexes, made it possible to combine local compensation of reactive power consumed by induction motors with a diagnostic system for monitoring and predicting the residual life of an induction motor. The purpose of the work is to predict the residual service life of the body insulation of induction motors due to the energy that remains in the capacitors at local compensation of reactive power and to develop software for the device implementing the method. To achieve the goal, the following tasks have been solved: the analysis of methods for predicting the residual life of the electric motor has been carried out, and the relationship between the change in the insulation resistance of the windings and the discharge time constant of the capacitor has been established. The most important result is the establishment of an unambiguous relationship between the insulation state and the value of the constant voltage attenuation time across the capacitor. The most significant result is that the change in the time constant was used for the first time as a criterion parameter for predicting the residual life of the dielectric properties of the housing insulation of an electric motor. The significance of the study is that the basic value of the attenuation time constant is the value obtained after the first disconnection of the electric motor from the network. A method has been proposed and software has been developed for a device that allows to control the partial-phase modes of the mains voltage and current circuits during the operation of the electric motor, and when the electric motor is disconnected from the network—to control the value of the insulation resistance of the stator windings of the electric motor and cable, as well as to predict the residual service life of the electric motor.