Hydraulic Drive System
A hydraulic drive-system is a drive or transmission system that uses hydraulic fluid under pressure to power hydraulic machinery. Hydrostatic is a term that refers to the transfer of energy from flow and pressure, not from the kinetic energy of the flow.
A hydraulic drive system consists of three parts: The generator (a hydraulic pump), driven by an electric engine, a combustion motor or a windmill; valves, filters, piping etc. (to guide and control the system); and the actuator (e.g. a hydraulic engine or hydraulic cylinder) to drive the machinery.
The video below explains how a simple hydraulic system works with animated simulation.
Check it out!