Method for controlling frequency converter to start plurality of large motors by using PLC

Abstract

The invention relates to the field of motor control, in particular to a method for controlling a frequency converter to start multiple large motors through a PLC. The method for controlling one frequency converter to start a plurality of large motors by using the PLC comprises the following operation steps of: 1, controlling a single motor to start, and then randomly starting the next motor; according to the invention, only one frequency converter is used, and single gradual starting is limited by a PLC program; after the PLC receives the starting instruction, the Y1 acts to start the KM1 andthe Y0 acts to start a frequency converter; when the frequency reaches 50.5 HZ, the auxiliary relay of the frequency converter outputs a passive switch signal to switch on x0, and the PLC stops the output of the y0 and the y1, Y2 starts KM2 after short time delay, the motor is started and operated at power frequency, the next motor can be started, and the like, so that the problems of simple structure, high failure rate, low automation degree, inconvenience in control and high investment cost of conventional starting of a self-coupling, a star-delta and a soft starter which are used at presentare solved.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a method for using a PLC to control a frequency converter to start multiple large motors. Background technique [0002] With the continuous development of society and the continuous expansion of the scale of industrial and mining enterprises, the power of motors used by industrial and mining enterprises is increasing. Due to the large starting current of high-power motors and the impact of 4 to 7 times the current on the motor during long-term start-up, the speed is accelerated. The aging of the motor shortens the service life, and the large current at startup causes a voltage drop on the grid, which greatly affects the operating quality of other equipment. However, the auto-coupling, star-delta and soft starters currently used are routinely started, and the structure is simple and faulty. High efficiency, low degree of automation and inconvenient control, high investment c...

AI Technical Summary

Problems solved by technology

[0002] With the continuous development of society and the continuous expansion of the scale of industrial and mining enterprises, the power of motors used by industrial and mining enterprises is increasing. Due to the large starting current of high-power motors and the impact of 4 to 7 times the current on the motor during long-term start-up, the speed is accelerated. The aging of the motor shortens the service life, and the large current at startup causes a voltage drop on the grid, which greatly affects the operating quality of other equipment. However, the auto-coupling, star-delta and soft starters currently used are routinely started, and the structure is simple and faulty. High efficiency, low degree of automation and inconvenient control, high investment cost

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