PRS2S18/30¡­300/515 is a kind of flexible soft starter with multi-functions which can replace start and is suitable for most of occasions. All the control connection and adjustable parameters are fixed on the obverse panel, which makes it easy to install and adjust. Thus working status and fault can be indicated clearly on the panel. Furthermore, this soft starter can be conveniently altered, for example: additionally add current-controlled function and alternative selectable in-line and inside-delta connection is possible. It can keep running without bypass. Controlling relay is specially designed for bypass and fault. All the parameters are set through 3 knobs and a switch. It can even keep working under such occasions with vibration and higher temperature. When the soft starter is connect in-line, it can bear 1.73 times current as much as when it is inside-delta-connected. For example, an S type soft starter with rated current 58A can bear 100A motor when being in-line-connected.