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August 1, 20234 min read

The Why and How of Replacing Traditional Hydraulics with Electric Actuators

This is a summary from the presentation by the same title by Kirk Martin, Global Director of Sales, Mobile Machinery at Ewellix, at the Future of Electrification 2023 conference. Watch the full session here: 

The use of electric actuators is on the rise, and for good reason. During his presentation at the Future of Electrification Conference, Kirk Martin, Director of Sales, Mobile Machinery at Ewellix, discussed the benefits and challenges associated with replacing traditional hydraulics with electric actuators.

According to Martin, electric actuators offer numerous benefits. First, they are more efficient than hydraulic systems and are well-suited for high-work-function applications that require a lot of power. This is particularly important as battery-powered machines become more prevalent. He also pointed out that they are a cleaner and more environmentally friendly option since they require no oil. This makes them ideal for environments where oil leakage is undesirable, such as golf courses.

When it comes to controllability, Martin explained that electric actuators outperform hydraulic systems as they exhibit minimal play, allowing them to execute precise and accurate movements with exceptional accuracy. They are well suited for tasks that require a high level of control, such as grading machine work. By utilizing a controller with position accuracy and actuator feedback, operators can program specific positions for the mechanism to halt and return to its loaded position. This level of control and precision empowers operators to achieve greater accuracy and efficiency in their operations.

Martin emphasized that electric actuators require less maintenance than hydraulic systems. This is because there are fewer parts in an electric actuator, meaning that there is less that can go wrong. Apart from occasional grease application in the gearbox and screw, there are usually no major maintenance requirements. As a result, downtime is reduced and maintenance costs are lower. He explained that this simplicity also translates to easier manufacturing processes. 

During his presentation, Martin also covered the challenges associated with replacing traditional hydraulics with electric actuators. One significant obstacle is the need to redesign the frame to accommodate the motor and gearbox that are typically required for electric actuators. This can result in a 10-30% increase in frame size, making them less of a drop-in replacement compared to other options. Additionally, careful consideration must be given to the position of the motor within the frame relative to the actuator. If the motor is positioned at the lower end of the actuator, it may extend beyond the boundaries of the frame, leading to a phenomenon referred to as tail-swing. Tail-swing can affect the overall dimensions and space requirements of the system and adds complexity to the integration process.

Martin mentioned the importance of properly sizing the electric actuator to meet the application's requirements. Determining the required force ensures that the actuator can effectively perform its intended task. In addition, Martin stressed the significance of considering speed. While larger motors generally offer higher speeds, finding the right balance between speed and energy efficiency is essential to allow for optimal performance without excessive energy consumption.

Choosing the appropriate voltage for the actuator is another important consideration noted Martin. The specific application and its power requirements play a crucial role in determining the optimal voltage. Higher voltage can provide better efficiency and reduced current, which is advantageous for high-power applications. On the other hand, lower voltage may be sufficient for auxiliary functions or less power-intensive operations. Martin added that safety protocols and the availability of motors and controllers should also be considered when dealing with higher-voltage applications.

According to Martin, the control package is an additional factor when making the switch to electric actuators that varies based on different applications. From simple relay-based start-stop functionality to more advanced systems providing position feedback or utilizing a full CAN bus network, selecting the appropriate control package is essential for the seamless integration of the electric actuator into the application's control system.

Martin explained, in rugged and dirty environments, such as those encountered by mobile excavators, electric actuators perform well if they are appropriately sized and designed with the necessary features. However, mechanical shock can be a concern due to the rigidity of electric actuators compared to hydraulic systems. Mechanical shock can occur when the actuator comes into contact with external forces or experiences abrupt changes in motion or direction. To mitigate this issue, it is important to incorporate shock-absorbing features, such as resilient materials, protective covers, or specialized mounting arrangements when installing an electric actuator.

While there are challenges associated with replacing traditional hydraulics with electric actuators, the benefits make it an increasingly attractive option for many applications. Efficiency, controllability, and lower maintenance requirements are just a few of the reasons covered in Martin’s presentation why electric actuators are becoming more popular. However, it is important to properly size and configure electric actuators for each application to ensure that they perform as intended.