Undersized pumps lack sufficient controlling pressure, resulting in a system that can't move at desired speed or decelerate to a target position quickly. Oversized hydraulic pumps are wasteful, as they cost more and require that oil be bypassed to the storage tank when the system isn't moving. As with pumps, correctly sized cylinders are critical. Accumulators Accumulators are energy storage devices, or reservoirs, for air or oil pressure. For best results, use accumulators of adequate size and place them close to the valves.
Accumulators serve two important functions.
First, they store energy so pumps don't have to be sized for peak loads. Second, when sized correctly, they keep the system pressure relatively constant. Thus, maintaining constant system pressure reduces the need to change gains as a function of pressure in the motion controller. This also provides for smoother motion when moving slowly. Oversized pumps don't replace accumulators.