Abstract: A hydrostatic fan drive is operated with a closed circuit and includes a variable-displacement pump with a swept volume that is configured to be adjusted by an adjustment device. The variable-displacement pump is connected by two working lines to a motor that is coupled fixedly in terms of torque to a fan impeller. The fan drive further includes a feed pressure pump and an adjustment pressure line by which the adjustment device is supplied with adjustment pressure medium. A pressure cut-off valve is connected to the adjustment pressure line. The pressure cut-off valve is configured to limit an adjustment pressure, as a function of a high pressure in the working line acting as high-pressure line, to a value such that a certain value of high pressure is not exceeded. The pressure cut-off valve is configured to exhibit pilot control to regulate a working pressure of the variable-displacement pump.

Abstract: A hydrostatic fan drive is operated with a closed circuit and includes a variable-displacement pump with a swept volume that is configured to be adjusted by an adjustment device. The variable-displacement pump is connected by two working lines to a motor that is coupled fixedly in terms of torque to a fan impeller. The fan drive further includes a feed pressure pump and an adjustment pressure line by which the adjustment device is supplied with adjustment pressure medium. A pressure cut-off valve is connected to the adjustment pressure line. The pressure cut-off valve is configured to limit an adjustment pressure, as a function of a high pressure in the working line acting as high-pressure line, to a value such that a certain value of high pressure is not exceeded. The pressure cut-off valve is configured to exhibit pilot control to regulate a working pressure of the variable-displacement pump.