Semiconductor soft starter 3RW3 Disadvantages: No prolonged speed setting possible. Lower torque with reduced voltage I M I Start 100% U Mains I Start x 0,7 I Start x 0,5 100% U Mains M Start 70% U Mains 50% U Mains 70% U Mains 50% U Mains x 0,49 M Start M Start x 0,25 n n Syn n n Syn Fig. 8-6: Current and torque profile when using a soft starter Rev. 08/99 8-9