Soft starter/brake for three-phase motor

Abstract

The invention provides a soft starter / brake for a three-phase motor, relating to the braking and starting fields of three-phase alternating-current (AC) motors. The soft starter / brake mainly comprises a singlechip and is characterized in that the continuity signal output by the singlechip is connected with an operating AC contactor by a silicon controlled thyristor (SCR); the brake signal output by the singlechip is connected with a braking AC contactor by an IGBT; the operating AC contactor is controlled by an operating switching signal; the braking AC contactor is controlled by the braking switching signal; the singlechip is controlled by control signal input; and the operating AC contactor and the braking AC contactor control a peripheral motor. The soft starter / brake has double functions of electronic brake and soft start, drives the mechanical equipment to softly start, realizes low-current electronic brake and can prolong the service lives of the motor and the mechanical equipment and save the electric energy.

Description

technical field [0001] The invention relates to the field of braking and starting of three-phase AC motors, in particular to a combination of starting and braking devices for three-phase AC motors. Background technique [0002] At present, the motors of large and medium-sized mechanical equipment are widely used to start with reduced voltage. When the motor 6 is started, a large starting current will be generated, which will have a large instantaneous impact on the power grid and the mechanical equipment. At present, various methods such as triangular step-down start, autotransformer step-down start, and series resistance step-down start are generally used, but none of them can solve the instantaneous impact problem well, and at the same time, many devices are used, which is prone to failure. As for the brake of the motor, there are generally two kinds of friction brakes and electronic brakes. The friction brakes mainly use friction plates. Due to the wear of the friction ma...

AI Technical Summary

Problems solved by technology

At present, various methods such as triangular step-down start, autotransformer step-down start, and series resistance step-down start are generally used, but none of them can solve the instantaneous impact problem well, and at the same time, many devices are used, which is prone to failure.

As for the brake of the motor, there are generally two kinds of friction brakes and electronic brakes. The friction brakes mainly use friction plates. Due to the wear of the friction material, the service life of the equipment is affected, and the accuracy is difficult to control and the safety is poor. Electronic brakes are generally It uses a high-power transformer to change 220V or 380V AC to 60V, uses a high-power potentiometer to adjust the voltage used for motor braking, and then rectifies it for motor braking.

The brake structure of this structure is large in size and heavy in weight, and the braking effect is poor at the same time

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