06
Mar
A soft starter is any device that can control the acceleration of AC electrical motors and reduce the torque and load in power train, as well as the electrical current surge of motors during start ups. When accelerating an AC electrical motor to full speed, a large inrush current is required. If the torque of AC motors is uncontrolled, it can shock the connected equipment, causing permanent costly damage. However, soft starters for motors are able to efficiently limit the torque and reduce the inrush currents, protecting the expensive equipment and expending the motor life.
Using a motor soft starter can help protect the motor and connected equipment from any sort of damage by controlling the voltage. Thus, the inrush currents will be limited and the mechanical shock reduced. The soft starters for motors can support either mechanical or electrical devices, but they can also support combined devices. Mechanical soft starters are clutches and some types of couplings, using fluids, magnetic forces and steel shot for transmitting torque, while electrical soft starters are all control systems able to reduce the torque by reducing the voltage or current input temporarily.
Soft starters are often compared to drives, but they bring few major advantages. First, soft starters for motors are far more efficient than drives, as they use solid state switches. Second, with soft starters, the starting current can be controlled conveniently by adjusting the starting voltage, which ensures a smooth start up of the motor. And when it comes to operational costs, soft starters provide better cost-efficiency than all traditional methods. Additionally, soft starters for motors are the perfect solution for space-limited applications, as they take up only a little space compared to drives.
Soft starters for motors can be adjusted according to the requirements of each particular application. Most commonly, soft starters are used in applications where speed ramping and torque control is needed when starting or stopping. Also, these devices are used to limit the high inrush currents during start-ups of large motors. Soft starts are also used to help in preventing pressure surges in piping systems when fluid changes speed too rapidly.
Soft starters for motors are quite common in pumping applications, because of their ability to avoid pressure surges. These devices allow a smooth start up of conveyor belt systems, which also helps in avoiding unnecessary stresses on drive components. All systems with belt drives can start slowly and smoothly with soft starters and avoid belt slippages. Regardless of the applications, soft starters limit the inrush currents, improve the power supply stability and reduce the voltage.
