Electric vs. Hydraulic Actuators: Why to Choose Electric

1. COSTS

HYDRAULIC: Most expensive overall costs

This includes the initial purchase, plus all costs over time, such as: maintenance and its labor costs, high energy costs, reduced equipment performance, decreased reliability, increased fluid costs, replacement costs, manufactured product scrap/yield and clean up costs.

ELECTRIC: Lowest total cost of ownership

50% lower energy costs, increased flexibility and production, lower product waste, increased product quality, lower maintenance costs, shorter changeover time, no environmental issues, faster ROI, and increased profits.

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2. MOTION CONTROL

HYDRAULIC: Limited motion control capabilities

It also requires a servo-hydraulic system to achieve better motion control, which adds cost and complexity and still isn’t as high control as electric.

ELECTRIC: Full control over position, velocity, acceleration/deceleration and current

Can provide sensor feedback on the motion and force applied, allowing for greater control over the motion. They can feature programmable stop positions; the electric actuators can stop at any position along their length, with high positioning accuracy.

• Need full control? An electric actuator system is your first choice.

3. PRECISION & SPEED

HYDRAULIC: Hard to control accurately

Hydraulic actuators often suffer from “stick slip”, jerking and jolting when moving after being still. Having multiple cylinders on one system can create problems or limitations with high speed, and as well as banging the end of stroke at higher speeds due to uncontrolled decal.

ELECTRIC: Very fast movement up to 10 m/s with easy, automatic operation controls

They also have a precise control of speed and deceleration providing smooth, non-violent motion.

• Gain needed speed with electric systems.

4. LOAD HOLDING & SAFETY

HYDRAULIC: Oil leakage and failure

Due to hydraulic actuators being powered by pumps of incompressible oil, the likelihood of oil leakages is high. Many companies ban hydraulic actuators from their facilities due to this safety issue.

ELECTRIC: No leaks and fail-safe brakes

Electric actuators don’t have messy or costly leaks like hydraulic systems. Most electric actuators contain acme screw units, which are fail-safe brakes, and self-lock in the event of a power failure.

• Electric systems are far superior in safety.

5. MAINTENANCE

HYDRAULIC: Long service life with frequent maintenance

Hydraulic actuators require regulator adjustment and flow control adjustment, as well as continuous operator and maintenance labor hours adjusting equipment to get more proper, consistent cylinder operation. Fluids, pumps, lines, oil, and filters all require checks, changes, cleaning, and replacements. Neglecting these could result in contamination, leaks or component failure.

ELECTRIC: Long service life with little to no maintenance

With electric systems, there are no risks of fluid leakages. Minor maintenance is mostly optional but suggested, and reduces costs and increases productivity for both the team and the table. These are made for the life of the application, are lubricated for life, have no seals to replace, and are consistent for a repeatable operation.

• If you don’t want to worry about maintenance, choose an electric system.

6. INSTALLATION

HYDRAULIC: Difficult with consequences if done incorrectly

This is a more complex system with more components and is very difficult to try to install unless you are highly educated on hydraulics.  If anything goes wrong, there is a large list of things it could be, whereas the electric motor can just be reprogrammed most of the time.

ELECTRIC: Easy, fast, and safe

Setting up electric actuators only requires simple wiring. They can also be networked and reprogrammed very quickly.

• All LTW electric products ship fully assembled. Simply plug the product into an outlet, and instantly raise its height with the touch of a button.

7. SYSTEM COMPONENTS

HYDRAULIC: External and not contained

For hydraulic systems this is not contained, and requires numerous external components.

ELECTRIC: No extra clutter

This system has no extra components.

• Like a neat shop floor? Choose electric.

8. ENERGY EFFICIENCY

HYDRAULIC: Work or loss

Hydraulic efficiency is estimated around 45% at 50% duty cycle. Energy put into a hydraulic system comes out as work or loss in the form of heat.

ELECTRIC: Efficient

Electric efficiency is estimated around 80% at 50% duty cycle. The cost kW/hr = approx .07

• Save electricity with electric systems.

9. WEATHER (HOT/COLD TEMPS)

HYDRAULIC: Prone to many problems

Hot weather can cause overheating, damage to seals, oil degradation, can require a reservoir and heat exchanger, and also requires constant attention and maintenance. In the cold, the actuators become sluggish. They become inconsistent with repeatability, causing damage to rod seals, and requiring added oil tank heaters.

ELECTRIC: Few troubles

Electric systems have much fewer problems with heat. They have quick, effective cold weather starts, with only a slight performance difference from cold to warm/hot temperatures. Electric systems have the highest heat resistance of all actuator options.

• No AC? No problem with electric actuators.

10. ENVIRONMENTAL FRIENDLY

HYDRAULIC: Part of the oil leakage problem

This is dirty and messy to operate, and will eventually leak oil. Oil leakage can result in significant safety and environmental hazards. NOAA (National Oceanic and Atmospheric Administration) says: “More than 700 million gallons of petroleum products enter the environment each year. Around half of this volume comes from irresponsible and illegal disposal. Hydraulics’ contribution is about 98 million gallons.”

ELECTRIC: Go green!

Electric systems are environmental friendly! With no oil, they are the energy efficient, “green” operation choice.

• No oil with electric systems.

11. NOISE

HYDRAULIC: Can be very noisy

ELECTRIC:  Quiet

• Working environments are noisy enough – electric actuators won’t add much to that.

12. FORCE CAPABILITIES

HYDRAULIC: Pressure fluctuations

Although this has a high force density per cylinder size, the pressure fluctuations affects repeatability and requires constant pressure (stored energy).

ELECTRIC: On-demand control

This has a medium force density per motor and is force control (current in motor). The electric current control is very repeatable, and with being instantaneous on demand, it couldn’t be simpler.

• Instantaneous control with electric.

13. OVERALL FOOTPRINT

HYDRAULIC: Large footprint with many components

This has a smaller cylinder size, but larger overall system footprint with more components to purchase and maintain.

ELECTRIC: Small footprint with few components

This does not require external pumps or motors and therefore, are a much smaller overall footprint and take up less space. This has a longer electric actuator, fewer components and simplified installation.

• Electric systems take up less of your valuable space.

14. DATA COLLECTION

HYDRAULIC: Possible with additional sensors

This requires an expensive Servo-Hydraulic system with addition sensors. The more components and complex the system is, the higher the probability of system issues.

ELECTRIC: Built-in

This is built into the electric actuator system, with the force coming from the electric current, and the feedback based on the position and velocity.

• If you need data collection, choose an electric system.

15. LOAD CAPACITY

Sources:

https://www.duffnorton.com/blog/hydraulic-vs-electric-linear-actuators
https://www.engineering.com/AdvancedManufacturing/ArticleID/16809/How-to-Decide-Between-Electric-Pneumatic-and-Hydraulic-Actuators.aspx
https://www.automateshow.com/filesDownload.cfm?dl=Dietrich-ElectricRodActuatorsvs_HyadraulicCylindersWhichisBestforYourApplication.pdf
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