Protection control system for direct starting of motor

Abstract

The invention relates to a protection control system for direct starting of a motor, which comprises a main circuit, a driving circuit, a sampling circuit, a display module and a protection control device for controlling the circuits, and is characterized in that the protection control device comprises a protection analysis module for performing protection analysis on a sampling current or voltage digital signal and outputting protection information; the tripping control module is used for sending a command to the protection information which firstly meets the tripping condition; and the starting control module enters a switching value output circuit DO for processing according to a starting signal sent by a switching value input circuit DI of the driving circuit, and correspondingly controls a corresponding relay on the switching value output circuit DO to work so as to correspondingly control a contactor KMA to be directly started. The protection control system for direct starting of the motor can prevent starting current from impacting a power grid and the motor, is reliable in operation, does not need to design a complex voltage reduction circuit, and is convenient for workers to operate and maintain.

Description

technical field [0001] The invention relates to a control system, in particular to a protection control system for direct starting of a motor. Background technique [0002] Motors can be used in many fields such as aerospace, automobile, electric power and chemical industry. Many devices in various fields adopt direct motor start control. Direct start means that the stator winding of the motor is directly connected to the power supply, and it starts at rated voltage and has a starting torque. The characteristics of large size and short starting time are also the simplest, most economical and reliable starting method. The current is about 5 times that of normal operation. In theory, as long as the capacity of the line and transformer that supplies power to the motor is greater than 5 times the capacity of the motor All of the above can be started directly. For large-capacity motors, on the one hand, the power supply line and transformer capacity are difficult to meet the con...

AI Technical Summary

Problems solved by technology

For large-capacity motors, on the one hand, the power supply line and transformer capacity are difficult to meet the conditions for direct start-up of the motor; The internal damage of the motor will affect the service life of the motor. Secondly, the start-up of a high-power motor will have an impact on the power grid. Therefore, a large-capacity motor needs to be started with a reduced voltage to reduce the impact of the current on the power grid. For example: Y / Δ conversion start, auto-coupling Transformer startup, etc., but the step-down startup causes the complexity of the control device circuit, and it is more difficult for operators and maintenance personnel, which is not conducive to operation and maintenance

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