High-performance soft starters provide gentle starting and stopping of three-phase induction motors

WEG has recently launched the SSW900 series of soft starters. These compact soft starters, which replace the current SSW06 soft starter series, are designed for industrial and commercial applications. As high-performance top-end devices with integrated PLC functionality, they provide fully programmable algorithms for regulating induction motors as well as fully flexible torque control. The new series covers output currents from 10A to 412A in the wide voltage range of 220VAC to 575VAC (three-phase) with four case sizes. Thanks to soft starting and integrated protection functions, the SSW900 ensures energy-efficient and reliable operation of electric motors. The device is suitable for a broad range of applications, including blowers and ventilation fans, axial, radial and centrifugal pumps, metering pumps, stirrers and mixers, conveyor belts, extruders, dryers and industrial ovens, turntables, and ball or hammer mills. Johannes Schwenger, head of product management Low Voltage and Medium Voltage Drive Systems Europe at WEG, comments: “The SSW900 series of soft starters expands our portfolio in an area which was previously not a focus of our activities in Europe. The new SSW900 devices are easy to use, and the integrated PLC allows the output torque to be adapted to the load and the start-up current to be kept as low as possible. Numerous protection functions are also integrated to ensure reliable operation of electric motors.” The soft starter supports direct motor connection in wye or delta configuration, as well as wye/delta switching with six motor leads. This allows the three motor phases to be wired directly to the three thyristor pairs of the devices. As a result, the soft starter only has to provide 58% of the rated motor current (corresponding to the phase current), allowing a smaller device to be used for the same power level. The device has an integrated bypass contactor for longer service life, optimal space utilisation and lower heat dissipation (nearly zero) in the switchgear cabinet. Ease of use is further enhanced by a real-time clock as well as diagnostic and status query functions. Three different stop methods and a kick-start function expand the scope of potential applications.