How the soft starter works

GW MB10F 0.8A 1000V rectifier bridge

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

Industrial Router Crystal 3.2*2.5mm 3225 26M (26.000MHZ) 12PF 10PPM 20PPM 30PPM

Photocoupler

Guide: Soft starter is a novel motor control device that combines soft start of motor, soft stop, light load energy saving and various protection functions. Let's learn how the soft starter works. .

1. Soft Starter Working Principle - Introduction

The soft starter is a novel motor control device that combines motor soft start, soft stop, light load energy saving and various protection functions. It is called Soft Starter in foreign countries. Its main component is a three-phase parallel thyristor connected in series between the power source and the controlled motor and its electronic control circuit. Different methods are used to control the conduction angle of the three opposite parallel thyristors, so that the input voltage of the controlled motor can be changed according to different requirements, and different functions can be realized.

2. The working principle of the soft starter - the startup mode

The soft starter is a novel motor control device that integrates the soft start of the motor, soft stop, light load energy saving and various protection functions. The domestic soft starter is the most famous with the peaceful hps2 series soft starter. Its main component is the string. A three-phase parallel thyristor connected between the power source and the controlled motor and its electronic control circuit. Soft starters generally have the following startup methods:

(1) ramp constant current soft start;

(2) ramp boost soft start;

(3) step start;

(4) Pulse shock start.

3. The working principle of the soft starter

The soft starter uses three opposite-parallel thyristors as regulators, which are connected between the power supply and the stator of the motor. This circuit is a three-phase fully controlled bridge rectifier circuit. The main circuit is shown below.

When the motor is started by the soft starter, the output voltage of the thyristor is gradually increased, and the motor is gradually accelerated until the thyristor is fully turned on. The motor operates on the mechanical characteristic of the rated voltage to achieve a smooth start, reduce the starting current, and avoid starting the overcurrent trip.

When the motor reaches the rated number of revolutions, the start-up process ends. The soft starter automatically replaces the completed thyristor with a bypass contactor to provide a rated voltage for the normal operation of the motor to reduce the heat loss of the thyristor and prolong the service life of the soft starter. To improve the efficiency of its work, and to avoid harmonic pollution in the power grid. The soft starter also provides a soft stop function. The soft stop is opposite to the soft start process. The voltage gradually decreases and the number of revolutions gradually decreases to zero, avoiding the torque shock caused by free parking. The voltage curves for soft start and soft stop are shown below.

Expand reading:

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