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.
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 ...