Soft starter for middle-high voltage solid motor

Abstract

The invention relates to a motor soft starter, more particularly a full digital-control middle/high voltage solid motor soft starter. The motor soft starter mainly comprises a digital microcomputer controller, a control power supply transformer, a power supply isolating switch, a power supply fuse protector, a main vacuum controller, a thermal overload relay, a bypass vacuum contactor and a silicon controlled rectifier module. Compared with the prior art, the motor soft starter which is formed by the series/parallel connection of a plurality of silicon controlled rectifiers, can meet the requirements of different current and voltage grades, control the output voltage by regulating the trigger angle of each silicon controlled rectifier; reduce the electrical and mechanical shocks on the power network, the motor and the linked equipment during the start-up process of the motor; and monitor the motor and provide the fault protection function after the motor start-up is completed.

Description

[technical field] [0001] The invention relates to a motor soft starter, in particular to an all-digital controlled medium and high voltage solid-state motor soft starter. [technical background] [0002] At present, the control function of the known soft starter is not perfect and lacks many protection functions, such as the impact of the current during the starting and stopping of the motor, the high capacity of the power grid, and the mechanical impact when the motor starts. For example, as the most widely used squirrel-cage asynchronous motor, it adopts the conditions for step-down starting: first, when the motor starts, the machine cannot withstand the impact torque of full-voltage starting; second, when the motor starts, its terminal voltage cannot meet the specification requirements ; The third is that when the motor starts, it affects the normal operation of other loads. [Content of the invention] [0003] In order to overcome the deficiencies of current motor soft ...

AI Technical Summary

Problems solved by technology

For example, as the most widely used squirrel-cage asynchronous motor, it adopts the conditions for step-down starting: first, when the motor starts, the machine cannot withstand the impact torque of full-voltage starting; second, when the motor starts, its terminal voltage cannot meet the specification requirements ; The third is that when the motor starts, it affects the normal operation of other loads