Method for operating hydraulic system of mobile working machine i.e. industrial truck, involves limiting driving torque of drive motor by limitation of electric current for limiting pressure prevailing in delivery side of pump

摘要

The method involves providing a hydraulic pump (2) i.e. gear pump, for supply of a hydraulic steering device (4) and a work hydraulic system (3) with pressurizing medium. A priority valve (10) is attached to a delivery side (6) of the pump for preferred supply of the steering device with the medium. A structural unit (20) is formed by the valve with the pump. Driving torque of an electric drive motor (30) is limited by limitation of electric current driving the drive motor for limiting and securing pressure prevailing in the delivery side of the pump between the valve and the pump. The drive motor is designed as an asynchronous engine i.e. three-phase alternating current asynchronous engine. An independent claim is also included for a hydraulic system for a mobile working machine.