The 15 series pumps are a variable displacement axial piston pump that is linked to an open loop to a fixed displacement axial piston motor. The displacement moves by a prime motor (electric motor or internal combustion or some sort) and the fixed motor is moved by the fluids are from the pump that is prompted by the machine to go. The pump flow is made by the path of the rotation and speed of the fixed motor output shaft. In turn it depends on the on how the pressure from the system to tell about the load the machine is carrying.

The charge pumps pressure on this circuit is restricted when the factory set it and by the operating relief valve. If there is any fluid that is not used is cleared out from the circuit that goes over this valve and goes thru the pump and motor housings and returned to reservoir.

If there is any leakage going on, especially in these closed loop circuits, it has to be restored back so there will be no cavitation. To fix this a fixed displacement pump or gerotor is used to push it into the prime mover down thru the variable displacement pump shaft.

And being that the pump/motor circuit is a closed loop and you can pressurized it to have two directional control check valves to send the charge pump flowing towards the low pressure side of the circuit.

If you need more info on how this works, give us a call at 800-361-0068

sales@htsrepair.com