A Series circuit of hydraulic power system and a parallel circuit were tested for driving multiple loads.
(1) In the series circuit, the hydraulic pump can be of smaller capacity than in the parallel circuit, but the pressure in the upper circuit is higher as it is the sum of the pressure which is required to drive the first hydraulic motor and the under circuit pressure. On the series hydraulic circuit the under circuit is affected directly by the dynamic characteristics of the upper circuit.
(2) In the parallel hydraulic circuit the circuit pressure does not become so high as in the series circuit but the capacity of pump has to be larger.
(3) Since the pressure compensated flow control valve acts accurately in the system the both of series and parallel systems for a couple loads operate stably with unbalanced loads on statical and dynamical.