Any manufacturing facility that uses hydraulics powered by conventional fixed-speed hydraulic power units (HPUs) has engineers and personnel who know all too well how large, noisy, and inefficient older HPUs can be. In the past, such features were simply an accepted part of the manufacturing environment. But now, advances in engineering and design have led to new variable-speed power units that are smaller, quieter, and more efficient, intended for use in a wide variety of applications, and can directly replace traditional hydraulic systems.

Like other types of variable-speed, electrically driven equipment, variable-speed HPUs are significantly more energy-efficient than their fixed-speed counterparts. In addition, with built-in sensors, diagnostics, and cloud capabilities, they can be easily connected to an IoT environment to deliver valuable productivity and predictive maintenance data. Altogether, these benefits make modern hydraulic power units an attractive alternative to traditional units for energy efficiency, reduced cooling requirements, lower noise levels and increased reliability.

For engineers that specify new equipment or are charged with updating or replacing older HPUs, variable-speed systems provide more efficient options to consider before choosing where to invest.

When replacing or retrofitting an HPU, manufacturing engineers are advised to consider some key metrics that differentiate modern hydraulic system design from conventional systems: size, noise, energy efficiency, connectivity, and total cost of ownership.

1. Size: The overall size of an HPU is determined largely by the size of its hydraulic fluid reservoir. For traditional HPUs, the generally accepted rule is to size the reservoir a minimum of three to five times the maximum pump flow, to allow for degassing (time enough for the oil to sit in the reservoir and air bubbles to rise to the surface). For example, to achieve a max flow of 150 L using this old rule requires an approximately 600-L reservoir, which occupies a considerable amount of space within the unit’s footprint.

Read more: Assessing Five Key Areas of Modern Hydraulic Power Units