Assembly Line Using Transfer Trolley Running on Rails is powered by the 36V single-phase (three phase) , which through sliding wire to complete. Ground step-down transformer control cabinet will be single phase (three phase) AC 380V step-down to single-phase (3Phase) 36V, sent to the flat car by the rail sliding wire, and then step-up (three phase) single-phase AC 380V by step-up transformers