Power controller comprising a pump (2), communicating with a reservoir (4) of oil hydraulic fluid, and provided with drive means (3) which in turn have supply means (5), characterized in that the said pump (2) is fitted inside the said reservoir (4), and is coupled to the said drive means (3) placed above the reservoir (4), the said pump (2), the said reservoir (4), the said drive means (3) and the said supply means (5) being enclosed in a casing (1; 7) which is at least partially removable, and the said casing being coupled to support means (6; 8) enabling the said controller to be transported.