Moog Industrial Group, a division of Moog Inc., featured a prototype for a new Electro Hydrostatic Actuator (EHA) at the SPS/IPC Drives Show 2011, held in Nuremburg, November 22-24. Combining hydraulic and electric technology in a self-contained system, Moog’s innovative EHA concept integrates high performance Moog products including a Servo Motor, Hydraulic Pump, Hydraulic Valves, Manifold, Accumulator, Controller and Software.

Moog’s engineers leveraged the company’s expertise in both electric and hydraulic technologies to develop this optimized energy-efficient and reliable system. Moog has been providing industry-leading EHA systems for flight controls for over 18 years and now has begun working with machine builders to apply this expertise to industrial applications that require high force, energy savings, environmental cleanliness and elimination of hydraulic piping.

“At Moog, we refer to ourselves as ‘technology-neutral’ because we design both hydraulic and electric solutions,” says Dr. Sherif El Henaoui, Moog Industrial. “Therefore we have developed a deep understanding of the advantages and disadvantages of each technology for particular applications. This solution leverages this know-how to create innovative hybrid designs that combine both technologies, in compact, reliable and highly efficient systems.”

Unlike an electric actuator, Electro Hydrostatic technology requires no screws or gearing. It differs from hydraulic actuators in that it requires no hydraulic piping, thereby reducing cost and improving reliability. The system is fully self-contained as all hydraulic and electric components are highly integrated in the actuator assembly.

Electro Hydrostatic Actuators receive power from an electric source by wire and transform a typically electronic input command signal into motion. EHA uses fluidic transmission between the electric motor and actuator. Motors rotate only when movement is demanded, saving energy and wear. Low duty cycle or actuation on demand applications, that require the high force density of a hydraulic system, can benefit greatly from the energy savings of an EHA system. EHA includes hydraulic components and fluid, both are self-contained within the actuator assembly, eliminating the potential of leaks and environmental contamination.

This hybrid solution of hydraulic and electric drive technology allows the selection of the benefits of both technologies: The low energy consumption of the electric system by power only on demand, the easy energy storage for the fail safe movement and the high reliability of the hydraulic system.

EHAs also offer a number of overall system benefits and cost savings. Moog’s EHA design offers machine builders high energy efficiency and reliability, reduced envelope size, less wear on components and up to 40% less weight. The self-contained EHA package removes the need for long hydraulic line lengths and rotary couplings, offering significant cost savings in applications such as oil & gas and power generation equipment. The integrated systems approach means greater reliability for the customer as less individual components are required, lowering costs and downtime. Redundancy and fail-safe features are also fully integrated offering minimal impact on cost, weight, envelope and reliability.

EHA is an ideal option for applications that have high force requirements and require redundant or advanced fail-safe systems, while also delivering energy, cost and environmental benefits. Typical applications include power generation, industrial machinery and oil & gas equipment.

“The motion control industry is seeking new technologies that address the need for better energy efficiency and reliability at lower weight and size,” concludes Dr. El Henaoui. “Smart systems like EHA hybrid technology offer a new and innovative solution suited to a range of industrial applications.”