Kpdz transfer trolley. its power is supplied with single-phase 36v low voltage unit. dc motor drive. \nthe working principle : ac 380v is transformed into ac 36v by way of transformer into rails, and then sent to the current rectifier on the truck, which supply 36v direct current to dc motor. \nadvantage: rails are electricity conductor instead of cable. you need not worry about rail circuit impacted, and staff wouldn\'t care about pulling or draging cable in case of injuring it.