Soft starter is a device used to control the starting current of an electric motor. It is a technology that controls the accelerated start of an electrical motor, thereby reducing the start-up power demand and mechanical stress. 

The soft starter ensures a smooth ramp-up in the motor's speed as opposed to the sudden surge of current experienced during direct-on-line starting. The importance of soft starter stems from its ability to provide a significant reduction in motor starting currents, which in turn minimizes voltage drops and electrical power demand. Ultimately, it leads to cost savings for the end-users and better efficiency for the electrical systems as a whole. 

Additionally, soft starters are environmentally friendly as they reduce carbon emissions, and their cost-effectiveness has increased energy efficiency. In conclusion, the soft starter is an essential component of modern electrical systems, providing smooth acceleration, lower mechanical stress, and maximum energy savings while ensuring an eco-friendly environment.