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  • Starting modes of asynchronous electric motors

    Most of the electric motors used in industry are squirrel cage induction motors. In modern industries, various types of starting and controlling asynchronous motors are used, the choice of the starting mode determines the necessary means of automating the electric drive, which directly affects the functionality and, accordingly, the final cost of the project. Direct starting is the most common way to start an electric motor. The main advantage of direct start is the maximum cheapness of the control scheme implementation. The disadvantage of direct starting is high starting currents, exceeding the rated ones by 3-8 times, which leads to increased wear of the windings and causes a reduction in the service life of the electric motor. A high initial starting torque is accompanied by a significant impulse, which places a significant load on both the mechanisms of the electric drive itself and the units of technological equipment. Star-delta starting is used to reduce inrush currents. It allows you to make a soft start with a star circuit, and during operation, a triangle is turned on, providing the maximum power of the unit. In contrast to the starting modes discussed earlier, the soft starter stabilizes the starting characteristics, providing a gradual increase in power and stable operation of the motor, which allows to extend the service life of the electric motor and technological equipment. The use of frequency converters allows you to optimize production, reduce energy consumption, and increase the service life of equipment. The inverter also protects the electric motor in the event of a short circuit, deviations from the nominal mains voltage and controls the operating temperature of the electric motor, preventing it from overheating. Having considered the features, as well as the advantages and disadvantages of starting modes of asynchronous electric motors, it is possible to determine what equipment is needed to implement a specific task of an automated electric drive.

    Keywords: automated electric drive, asynchronous electric motor, starting mode, soft starter, frequency converter, automatic control