Hydraulics and Pneumatics

Chapter | two. Hydraulic Pumps and Pressure Regulation

A hydraulic pump (Figure 2.1) takes oil from a tank and delivers it to the rest of the hydraulic circuit. In doing so it raises oil pressure to the required level. The operation of such a pump is illustrated in Figure 2.1a. On hydraulic circuit diagrams a pump is represented by the symbol in Figure 2.1b, with the arrowhead showing the direction of flow.

Figure 2.1 The hydraulic pump

Hydraulic pumps are generally driven at constant speed by a three-phase AC induction motor rotating at 1500/1000rpm in the UK (with a 50Hz supply) and at 1200/1800rpm in the USA (with a 60Hz supply). Often pump and ...