Hydraulic power packs
are used in countless applications, from steel mills, galvanizing plants and various steel finishing plants to amusement park and locomotives. The hydraulic power pack is used for transferring power from one location to other by using hydraulic motors. A heater (or a heat exchanger) attached to the power pack helps maintain the oil at designed viscosity.
An electric induction motor runs at constant speed to deliver the hydraulic oil at a constant pressure to the hydraulic circuit. The flow meter in the line indicates the flow when the work is being done by the hydraulic oil under pressure. When the work is done, the oil is flowing and the pressure drops (see the plot below).