A hydraulic pump is a primary component that converts mechanical energy into pressure energy, making it easier to transfer power by driving fluid under pressure. It is commonly used in industries like agriculture and oil production.

A hydraulic motor operates on the same basic principle, but instead of using pressure to move fluid, it uses fluid pressure to drive a mechanical shaft, creating rotational force. Essentially, a hydraulic motor converts hydraulic energy back into mechanical energy.

In industrial applications, there are many types of hydraulic pumps. The three most common types are: the power source based, the pump action based and the positive displacement pumps.

A hydraulic pump is the power source in a hydraulic system, determining the system’s pressure and flow rate. Selecting the right pump involves considering the required pressure, flow rate, cost, stability, and accuracy of the system. It’s also essential to weigh the advantages and disadvantages of each pump type before making a final choice.

Compared to open-circuit systems, closed-circuit hydraulic systems offer the following advantages:

• A variable pump in a closed-circuit hydraulic system has the dual function of adjusting both flow rate and direction, allowing continuous control of the motor’s output shaft speed and rotation direction. Unlike an open-circuit system, it doesn’t require a directional valve in the main circuit, which keeps the main circuit simple and reduces fluid flow losses.
• The system has good rigidity and fast response. The refill system also serves as both a variable unit and a source of control pressure for other hydraulic systems.
• The circulation flow between the main circuit and the hydraulic tank is typically 20-25% of the main circuit's maximum flow or less. This requires a smaller hydraulic tank, only about one-third the size of that needed in an open-circuit system with the same power. This compact design is especially useful for vehicles and mobile machinery with limited installation space.