Every hydraulic system requires a source of hydraulic energy to operate. Hydraulic energy, in the form of pressure and flow, stems from your hydraulic power unit's pump. An electric motor converts, you guessed it, electrical energy into mechanical energy at its shaft. That mechanical energy gets converted once again into the hydraulic energy described above, which is the hydraulic pump's primary function.
Power unit design starts with understanding the actuators (cylinders and/or motors) to be powered. You must first specify the size (bore or displacement) of the actuators required to achieve their respective functions' force or torque. Those functions must operate within your desired cycle time. Speed is factored into the equation to understand that large cylinders and motors will move more slowly for any given flow input.
You can mix the ingredients of bore/displacement within any pressure range with the understanding you're limited by your input horsepower. A high horsepower pump and motor combination doesn't quite increase exponentially but is more costly than most realize. Considering this, you can run large actuators at low pressure and higher flow. Conversely, you may run smaller actuators at higher pressure to achieve the same result. The latter is ideal since smaller actuators, smaller power unit and smaller components will suffice. Don't confuse small with less powerful.
After the power requirements are calculated and decided upon, the control package must now be designed. The valve package controls the pressure and speed of the hydraulic system as a whole. It is tailored to suit individual actuators as well. If one actuator requires less flow and pressure than another, valves are added to reduce flow and pressure in its subcircuit alone.
After the control valves come the remaining components that compliment your hydraulic system and power unit, filtration, cooling, monitoring and conditioning elements are now selected. The scope of these options is often at the whim and budget of the customers. Here's a tip; get as much as your budget permits. You or your customer will be happier in the end.
I'll bet many of your reading this didn't know Higginson Equipment now manufactures hydraulic power units to compliment our NFPA cylinders. Our Hengli and Steed product lines perfectly complement any hydraulic system's needs, and with on-staff IFPS Certified Fluid Power Hydraulic Specialists, you know you design is in good hands. Reach out today to see what Higginson can do to supplement the exceptional cylinders you already buy from us!