A hydraulic power pack is a stand-alone assembly consisting of a drive motor, hydraulic pump and hydraulic fluid tank. The drive motor is connected to the hydraulic pump via a shaft and drives this. The motor and pump can be installed on the tank, as well as inside the tank in oil. The tank size, withdrawal, feed and critical flow speeds depend on the task and application, and must be configured accordingly. The extracted volume is determined in accordance with the size of the consumers and thus the overall need for fluid in the hydraulic system. The warming of the fluid, as well as potential leakages must be taken into consideration here. The critical flow speed occurs at the smallest diameter. The pump is driven by the electric drive and converts the electrical energy into hydraulic energy. This is also referred to as hydraulic pressure being created and a flow rate being provided. Using connections enables this to be used for drive in machines.