The compact power unit CO1 operates as part of the accumulator charging function. This means it is "always ready for operation but does not consume any energy". The hydraulic accumulator is always charged with oil up to the upper setpoint of the pressure switch，the power unit is switched off. The hydraulic functions are carried out and supplied with oil from the accumulator until the lower setpoint of the pressure switch is reached. Then the power unit switches back on automatically and recharges the accumulator. The integrated pressure filter ensures that only clean oil reaches the consumers and this results in a high level of system availability. Furthermore there is the option of installing an additional 3/2 directional poppet valve in the valve cavity in the flange. This allows a hydraulic function (e.g. tool release) to be added without having to install an additional block.