1. This softstarter controller control schematics reference to ABB PST series bypass contactor circuit diagram.This device is the external connection way, grade 10, used for 160kW and 75kW motor.the manufacturers must product with this control schematics diagram, and considered the layout of the electrical components .Softstarter control cabinet must be ventilation and heat dissipation , both the number of the fan and air flow depend on the requirements of PST series. 2. The manufacturers designed the current transformers CT1~CT3 .