Variable speed drive application on a press brake: Energy efficiency and economic analysis

In this study, the variable speed drive in hydraulic systems (VSDS) has been investigated. It was purposed to determine the amount of the energy that will be saved when the drive speed is controlled as per flowrate demand of the system in a traditional hydraulic system in which a fixed displacement pump is used. For this purpose, several tests were performed on a test rig to find the electricity consumption of the motor under variable load and flowrate conditions. Results were implemented to a press brake's cycle as a case study. Besides, economic analysis were made for a case that a press brake with fixed speed drive system (FSDS) is modified to VSDS and were repeated for 3 different annual operation scenerios. In conlusion, it was found that energy saving ratio of VSDS is between %4 and %19 for one press cycle. In the scenario that the VSDS gain is least, pay-back time, rate of repayment and present value worth were calculated as 38 months, %45 and 23.090 TL respectively.