Variable pump with high efficient energy saving and high precision proportional of pressure &flow makes the hydraulic output power alwaysmatches the required power of the machine, without any energy loss via the overflow valve. Compared with fixed pump, it could save energy by30-60%. By the way, it is suitable to equip more large pump volume for speeding up the machine meantime extend the life of sealing parts dueto low oil temperatue in case keeping the same eletric motor power.