Non-Destructive Test Method for Diagnosing Turn-to-Turn Circuits of Electric Motor Windings Under Conditions of Local Reactive Power Compensation

Modern automated technological complexes use an induction motor in both regulated and non-regulated electrical wires. Induction motors consume from 60 to 80% of the total electricity consumption of the electrical complex, and the reactive power consumption is from 45 to 65% of all electrical equipment. An effective means of reducing electricity losses in the power supply network by up to 15% is compensation of reactive power as comprehensively, and locally. Increasing the economic efficiency of the enterprise is also the prevention of emergency failure of electrical equipment. In particular, electric motors. The aim of the work is to study the use of energy remaining in phase capacitors at local reactive power compensation for test control of damage to the coil insulation of the stator windings of the electric motor and to develop a device for continuous diagnostics and protection of the electric motor. To achieve this goal, the following tasks were solved: the analysis of thermal, frequency, resonance and electrical methods for diagnosing the state of the coil insulation of the windings of electric motors was carried out, the characteristic roots of the second-order differential equation were analyzed, the relationship between the change in the number of turns in the windings of the electric motor and the time of the transient process of the phase capacitor discharge was established. The most important result is the use of energy that remains in phase capacitors when they are disconnected from the power supply, testing of turn-to-turn insulation at the time of the onset of a technological pause, establishing an unambiguous relationship between the time value of the transient period and the number of damaged turns in the winding. The most significant result is that the time value of the transient period is used for the first time as a criterion parameter for assessing the state of the turn-to-turn insulation of an electric motor. The significance of the study is that the value of the intact winding is taken as the base value of the transient period time. A method and device are proposed, which allow to control the partial-phase modes of the supply network voltage and the integrity of the current circuits during the operation of the electric motor, and to control the state of the interturn insulation of the stator windings of the electric motor when the electric motor is disconnected from the network.