The devices in four frame sizes enable soft starting of motors in standard applications such as pumps, conveyor belts, or fans up to 55 kilowatts at 400 volts. The Sirius 3RW30 soft starter improves the startup characteristics of motors with two-phase polarity balancing, and avoids mechanical loads, voltage fluctuations, and current peaks. This protects not only the drive system but also the power network and thus minimizes maintenance overhead and expensive current peaks. The user can easily set the startup time and the starting voltage using two potentiometers on the device. In the 45-millimeter frame size, the 3RW30 takes the place of a star-delta switch and saves up to 70 percent of control cabinet space while delivering the same performance power. The device can be easily configured and installed using three motor leads and variable connections.