IMPLEMENT AND STEERING HYDRAULIC SYSTEM CONTINUED
The pump is only at the zero swashplate angle when signal oil pressure suddenly drops to zero or when system
pressure suddenly surges to the maximum pressure cutoff setting. These conditions can cause the swashplate to
move momentarily to the zero angle position.
The compensator valve keeps pump oil flow at a level that is needed to fulfill the system load and flow needs.
These needs are met by the compensator valve in two ways: Either pump oil is sent to the large actuator piston or
pump oil is drained from the large actuator piston. The large actuator piston works with the small actuator piston
and the spring in order to continually adjust the swashplate angle. Pressure at the pump outlet is kept at about
305 psi (2,100 kPa) above the signal oil pressure by the margin spool in the compensator valve. The compensator
valve also has a pressure cutoff spool that prevents overloads of the pump and of the system. When work port
pressure goes over 5,585 psi (38,500 kPa), the cutoff spool will override the margin spool and lower pump output
while system pressure is maintained at 5,585 psi (38,500 kPa).
Figure 12. Pump and Compensator Operation (Engine Off).