The hydraulic pump may be the element of the hydraulic system that takes mechanical energy and converts it into fluid energy in the kind of oil flow. This mechanical energy is taken from what is called the prime mover (a turning drive) such as the power take-off or directly from the pickup truck engine.
With each hydraulic pump, the pump will be of the uni-rotational or bi-rotational design. As its name implies, a uni-rotational pump is made to operate in one direction of shaft rotation. However, a bi-rotational pump has the ability to operate in either direction.