The ABB PSTB1050-600-70 is a high-power, heavy-duty medium-voltage soft starter from ABB's PSTB series, designed for the controlled starting and stopping of very large three-phase induction motors. This advanced unit utilizes thyristor technology to provide smooth, stepless acceleration and deceleration, dramatically reducing the mechanical and electrical stresses associated with direct-on-line (DOL) starting. It is engineered for the most demanding industrial and infrastructure applications where motor and driven equipment protection, power quality, and operational reliability are paramount.