ABSTRACT
A common problem in circuits with pressure-compensated, variable-displacement pumps is incorrect setting of the compensator cut-off pressure in relation to the spring setting of the system relief valve. The relief valve must always be set higher-typically 100-150 psi-than the compensator. The reason is that if the compensator is set higher, part or all of pump output will flow over the relief valve when system pressure reaches the relief valve setting. The compensator will, in effect, be bypassed and the operating concept for which the system designer specified pressure compensation will be negated. In addition, fluid temperature will rise due to the energy loss resulting from the pressure drop over the relief valve.
