Thread Content
The main types of soft-start devices designed by manufacturers of chain conveyor systems are as follows: (1) Current-limiting start for chain conveyors； A soft start method that limits the starting current of the motor to not exceed a certain set value during its startup process. Its output voltage rises rapidly from zero, until the output current reaches the preset current limit IS; thereafter, the voltage increases gradually while keeping the output current constant, until the rated voltage is reached. Gradually increase the motor speed until it reaches the rated speed. The advantage of this starting method is that the starting current is low, and it can be adjusted as needed. It has a minimal impact on the power grid; its drawback is that it is difficult to determine the starting voltage drop, preventing full utilization of the available voltage drop margin. The loss torque is detrimental to the motor. (2) Slope voltage start of chain plate conveyor ； This starting method is the simplest; it lacks current closed-loop control, and it only adjusts the conduction of the thyristors so that it increases in a certain functional relationship with time. As the name implies, the voltage rises in a linear, ramp-like manner from low to high. It transforms traditional step-down starting into a continuous-starting method, and is primarily used for heavy-load starting. Its disadvantages include low initial torque, a torque profile that is parabolic in shape which is unfavorable for the driven system, as well as long starting times that can be harmful to the motor. (3) Torque control start of the chain conveyor ； It is used for heavy-load starting, where the starting torque of the motor increases linearly from low to high. Its advantages include smooth starting, good flexibility, and better protection for the drive system; its purpose is to protect the drive system and extend its service life. It also reduces the impact on the power grid during motor startup, making it the optimal method for heavy-load starting; its drawback is that the startup time is longer.