Softstarter is a device that is used to reduce the load and torque during the start-up of motors. A soft start improves the stability of the power supply and reduces voltage drops that may affect other equipment.
It is compulsory that user adds the soft starter between two busbars and one of the buses isn‘t an infinite bus. Once the soft starter is added, double clicking the component will bring up a parameters window depicted in Figure 3.21.
The user should define nominal power which is usually written in manufacturer’s catalog. It is also possible to add a current limit which will not allow current to exceed a defined value. Furthermore, the user may define the characteristic at which the soft starter will manage the voltage throughout the time of motor starts.
Defining the curve is very similar to defining the U/f characteristic of the frequency changer. To add new points to the curve, click add to add a point to the end of the list. Time t is measured in seconds and voltage is measured per unit. This means that the maximum value must not be bigger than 1.
