Throughout the construction industry, there is a need to make machines safer, more energy efficient and to reduce their emissions.
Despite that, many of the heavy-duty machines have demanding work cycles, meaning they cannot embrace full electrification. Instead, there needs to be a hybrid solution - but with two options available in EHA and EHP, which one will provide the most benefits?
EHP stands for Electro-Hydraulic Pumps. They work in a similar way to a conventional system but without any internal combustion and are controlled by a high-performance mobile hardened drive. Working to save expenditures rather than recovering energy, they use power on demand in addition to working under various pump and unit speeds.
EHA stands for Electro-Hydrostatic Actuator systems and has been earmarked as a potential solution of tomorrow. Currently being used within the aerospace industry, EHA systems work without valves, so that every function of the machines are dependent on each other. As a self-contained hydraulic system, it integrates one cylinder and a single feedback unit. There is also one servo motor and one variable speed pump as well as a single electric drive. Compact and highly efficient, EHA systems only need an electrical connection in order to work.
Both EHP and EHA represent a step forward from the way construction machines currently operate. For most construction machine manufacturers, the determining factors when it comes to deciding between EHA and EHP will be the type of application and the duty cycle.
How far the manufacturers are looking into the future could also be considered. There is no doubting that EHP is the easiest option. It makes product selection simple, it is cheaper than EHA and it can be fitted to existing systems.
EHA, on the other hand, is likely to result in significant costs. It represents a complete departure from the conventional system and cannot be retrofit to current construction machines. As the aerospace industry has proved, however, EHA drastically reduces weight and provides much better efficiency than EHP which results in significant fuel savings.
This article was contributed by Björn Eriksson, Senior Systems Engineer and Adrian Butler, Industry Market Manager