Starting method and precautions of solid state soft starter

The solid-state soft starter is also a kind of soft starter. What is the difference in the starting method of this kind of instrument when it is in use? Here is a brief explanation for everyone.

1. Full pressure start

In this state, the soft-start device is equivalent to a solid-state contactor, and the motor is the same as a direct start, and it bears all current and torque shocks. Under normal circumstances, the thyristor full-open time is controlled within 0.25s.

2. Current limit start

Current limiting starting, as the name implies, is to limit the starting current to below a certain set current value during the motor starting process. It is mainly used for relatively light load starting and certain requirements for grid impact. Its input voltage increases rapidly from zero until its current reaches the preset current limit, and then it is ensured that the output current is not greater than the current In the case of the limit value, change the conduction angle of the thyristor and gradually increase the voltage until the rated voltage. At the same time, the speed of the motor is gradually increasing, reaching the rated speed. The advantage of this kind of starting is that the starting current is small, the impact of the motor starting on the power grid can be minimized, and the current limit value can be set as required. But when setting the current limit, it must be set according to the initial torque of the motor. Otherwise, if the setting is too small, it will fail to start or burn the motor. The starting time of this starting mode is relatively long.

3. Pump controlled start and stop

Due to the relatively special mechanical characteristics of water pump loads, some soft-start manufacturers have specially designed pump-controlled starting and stopping methods for the characteristic curves of pump loads. This starting method can smoothly accelerate and decelerate the motor to make the centrifugal pump operate Reduce water hammer impact during start and stop. The main control circuit analyzes various operating parameters of the motor by collecting signals, and at the same time controls the state of the motor by changing the conduction angle of the thyristor, so as to reduce the possibility of the system being impacted by surge.

4. Voltage ramp start

This mode is a long-term starting mode. By reducing the impact of the starting torque, it realizes the smooth and continuous stepless acceleration of the motor to start, thereby minimizing the friction of gears, couplings and belts. The user can adjust the initial torque of the motor. During the acceleration ramp time, the input voltage of the motor rises linearly from the voltage corresponding to the set initial torque. The traditional step-down starting is changed to stepless, which can make the motor smooth Start, reducing the mechanical impact.

5. Sudden jump start

This starting method is mainly used in a relatively heavy work environment. On the basis of torque control, a sudden jump torque is used to overcome the static torque of the load at the moment of starting, and then the torque gradually rises until the motor reaches the normal working state. The advantage of the starting method of this solid-state soft starter is that it can shorten the starting time and start a heavier load, but it will have a certain impact on the power grid when starting, affecting the work of other loads under the same power grid.