This circuit has a variable displacement axial piston pump that goes into a closed loop and ends up going into a fixed displacement axial piston motor. The variable is made to go by a prime mover or an electric motor and the fixed motor goes by the fluid from the pump. The machine make a hoist, conveyor or equipment truck go. When you have machine load it is done so by the system pressure. The output shaft goes by the flow from the pump by means of the direction of the speed and rotation from the fixed motor.

Sometimes these pumps and motors have internal leaks, which is taken out thru the closed loop circuit. You will have to put more in oil so that it doesn’t close up on itself. To do this you will need a fixed displacement pump, some kind of gerotor. The prime motor makes it go by means of a variable displacement pump shaft. The charge pump gives a pre-determined volume of fluid that the pump or motor uses on the circuit to put back the fluid that it losses. This is a closed circuit, so that means both sides are pressurized. You will need two directional control check valves to make sure the charge pump flows toward the low pressure side of the circuit. The factory sets the amount of pressure in the charge pump by direct operating relief valve. If there is fluids that is leaked out, it goes thru the pump and motor housing and ends up in the reservoir.

If we can answer any questions on this, call us at 800-361-0068

sales@htsrepair.com