Home
Electric vs. Hydraulic and Pneumatic Actuators: Differences, Pros and Cons, and Selection Criteria
Electric actuators differ from hydraulic and pneumatic ones primarily in their energy source and the method used to generate motion. An electric actuator employs a motor and a screw mechanism; a hydraulic one uses pressurized fluid; and a pneumatic one uses compressed air. These differences impact force, precision, dynamic performance, control capabilities, and operational requirements.
No single technology is best for every machine. Hydraulics excel in applications requiring very high forces, while pneumatics are ideal for simple, rapid movements; electric drives, meanwhile, offer extensive possibilities for programming position, speed, and motion profiles. Importantly, modern industrial electric actuators can now generate forces that were until recently the exclusive domain of hydraulics.
How is an actuator constructed?
Regardless of the technology, an actuator’s function is to convert available energy into controlled mechanical motion. This typically takes the form of linear movement of a piston rod, carriage, or other actuating element.
The primary difference lies in the method of force generation.
Construction of an electric actuator
A typical electric actuator may consist of:
● an electric motor,
● a drive screw,
● a nut,
● bearings,
● a piston rod or carriage,
● a housing,
● a coupling or gearbox,
● position sensors or an encoder.
The motor drives the screw in a rotary motion, and the screw-and-nut mechanism converts this into linear motion. This enables the actuating element not only to move between end positions but also to stop at multiple programmed points. In practice, the design and operating principle of electric actuators directly influence the drive’s potential force, speed, accuracy, and duty cycle.
Hydraulic actuator construction
A hydraulic actuator utilizes a working fluid supplied to the cylinder under pressure. Its basic components include the cylinder, piston, piston rod, seals, and ports.
The complete system also requires, among other things, a pump, a fluid reservoir, lines, and control valves.
Pneumatic actuator construction
In a pneumatic actuator, compressed air acts upon the piston. While the cylinder design itself may be relatively simple, the entire system requires a compressed air source, air preparation equipment, lines, and valves.
Furthermore, the compressibility of air makes achieving high rigidity and precise position control more difficult than with a properly designed electromechanical drive.
What types of electric actuators are available?
Electric actuators differ primarily in their motion transmission mechanism, guidance design, motor type, maximum force, and permissible duty cycle.
AMG Automatyka’s product range comprises two main categories.
Tolomatic industrial electric actuators are designed for demanding applications, including continuous operation and processes requiring high forces. The range includes solutions capable of forces from a few kN up to 445 kN, featuring screw-driven, rod-style, and rodless designs.
In contrast, Concens linear actuators are compact DC gear-driven units designed primarily for intermittent operation. The typical duty cycle for this group is 10%, making them well-suited for mechanisms that perform a short movement followed by a prolonged period of inactivity.
Industrial electric actuators for high-duty cycle
Tolomatic’s industrial designs can utilize ball screws, lead screws, or—for very high forces—planetary roller screws. These solutions are compatible with servo motors and stepper motors and can be configured for specific applications.
A particularly notable example is the RSX electric actuator. This series was designed as an electromechanical alternative to hydraulics and comprises five sizes generating maximum forces ranging from 89 to 445 kN. RSX actuators are capable of 100% duty cycle operation, utilize planetary roller screws, and—depending on the variant—achieve speeds of up to 760 mm/s and strokes of up to 1500 mm.
For lower yet still substantial loads, RSA and RSA-HT actuators are suitable choices. The RSA-HT series is specifically designed for harsh environments, offering forces up to 58 kN, strokes up to 1524 mm, and an IP67-rated option. Variants with either ball screws or planetary roller screws are available.
Electric linear actuators for low-duty cycle
In many applications, the drive does not operate continuously. Adjusting a throttle, opening a flap, or repositioning a machine component may take only a few seconds, followed by a standstill lasting several minutes.
Concens actuators perform well in such conditions.
The CON electric actuator features a compact design and operates with an external controller. Depending on the variant, it offers a force of 120 to 10,000 N, a stroke of 50–750 mm, a speed of 3–70 mm/s, and a 12 or 24 V DC power supply. The standard housing offers IP66 protection, while versions for more demanding conditions are available for selected models.
If integrating electronics with the drive is important, an interesting alternative is the ICON actuator with an integrated controller. It retains the force range of 120–10,000 N and stroke range of 50–750 mm, while offering Modbus RTU communication via RS-485, motion parameter configuration, and the ability to synchronize the operation of up to eight actuators.
How does an electric actuator work? Motion diagram
The operating principle of an electric actuator typically involves converting the motor’s rotary motion into linear motion using a screw mechanism.
A simplified diagram looks like this:
Controller → electric motor → coupling or gearbox → screw → nut → piston rod or carriage → load
For example, if the screw pitch is 10 mm per revolution, one full rotation results in a theoretical displacement of 10 mm. The position can then be controlled via motor management and feedback systems.
This allows the electric actuator’s operation to be precisely tailored to the process—enabling the programming of position, speed, acceleration, and the approach profile to the target point.
Single-acting vs. double-acting actuators – what is the difference?
The distinction between single-acting and double-acting actuators applies primarily to hydraulics and pneumatics.
In a single-acting actuator, the medium drives motion in only one direction. The return stroke is achieved via a spring, the weight of the component, or an external force.
In a double-acting actuator, the medium can be supplied alternately to both sides of the piston. This allows for the active driving of both the extension and the return strokes. With an electric drive, a change in direction results from reversing the motor’s rotation, so such a division is unnecessary.
How does a double-acting pneumatic cylinder work?
A double-acting pneumatic cylinder has two working ports. Air supplied to the first chamber moves the piston in one direction; once the valve switches, air enters the chamber on the opposite side, causing the return stroke.
A simplified diagram can be represented as follows:
pressure in chamber A → extension
pressure in chamber B → retraction
This solution is simple and fast, but precisely stopping the piston at multiple arbitrary points requires a much more complex system than that of an electrically controlled linear actuator.
Electric, hydraulic, or pneumatic actuator – a comparison
| Criterion | Electric | Hydraulic | Pneumatic |
| Energy source | Electrical energy | Pressurized fluid | Compressed air |
| Position control | Very good | Good with advanced control systems | Limited in simple systems |
| Multiple programmable positions | Easy to implement | Possible | More difficult |
| Speed control | Very good | Good | Good for simple movements |
| Very high forces | Possible with appropriate designs | Excellent capabilities | Lower than hydraulic systems |
| Rigidity | High | High | Lower |
| Auxiliary equipment | Power supply and controls | Pump, reservoir, lines, valves | Compressor, lines, valves |
| Risk of medium leakage | None | Yes | No working fluid |
| Motion programming | Very extensive | Requires appropriate controls | Limited in simple systems |
| Typical profile | Multi-position, programmable | Heavy loads | Rapid point-to-point movement |
It is worth noting that the limit regarding maximum forces has shifted significantly. The industrial RSX model offered by AMG achieves up to 445 kN; therefore, in certain processes, an electromechanical solution can directly replace a hydraulic cylinder.
What are the advantages of an electric actuator?
The greatest advantage of an electric drive is the ability to precisely control motion without the need for a separate hydraulic or pneumatic system.
Programmable positioning
The controller can determine position, speed, acceleration, and direction of movement. Consequently, a single axis can execute multiple different positions within one cycle.
Easy adjustment of process parameters
Stroke, speed, or stop positions can be changed via software, eliminating the need for mechanical limit switch adjustments.
Control over the entire motion profile
The actuator can rapidly advance the tool toward the workpiece, decelerate before contact, perform the actual operation at a controlled speed, and then quickly retract.
Reduced infrastructure requirements
Electric drives do not require hydraulic pumps, oil reservoirs, or centralized compressed air systems. Programmability and the ability to operate without extensive hydraulic or pneumatic infrastructure are core design principles of Tolomatic industrial actuators.
Integrated control capabilities
The ICON model is an example of this, featuring a controller built directly into the unit. Modbus RTU communication via RS-485 and multi-axis synchronization capabilities reduce the number of separate components required to build the system.
What are the limitations of electric actuators?
An electric drive is not automatically the best solution for every application.
For simple point-to-point motion—where compressed air infrastructure is already available at the facility—a pneumatic cylinder may be a simpler and more cost-effective solution.
Hydraulics remain an attractive option for applications requiring very high forces within a compact space, especially when a hydraulic system is already in place.
For electric actuators, however, special attention must be paid to:
● screw selection,
● axial load,
● speed,
● duty cycle,
● temperature,
● load guidance method,
● motor parameters.
It is also important not to treat all electric actuators the same way. The industrial RSX model can operate with a 100% duty cycle, whereas compact Concens designs are typically intended for intermittent operation with a 10% duty cycle.
When should you choose a hydraulic actuator?
Hydraulics remain a good solution where very high force is the priority and precise programming of multiple positions is not a primary requirement.
Typical examples include:
● heavy-duty presses,
● construction machinery,
● lifting systems,
● heavy-duty clamps,
● mechanisms operating under extreme loads.
However, this does not mean that every high-force application requires hydraulics.
For pressing, bending, clamping, or durability testing, it is also worth considering the RSX electric actuator, which was designed specifically as an alternative to hydraulic systems. Its force range of 89–294 kN allows it to be used in heavy industrial processes as well.
When should you choose a pneumatic actuator?
Pneumatics work well for simple, rapid movements, especially when two end positions are sufficient. It can be a good choice for:
● product pushing/ejection,
● simple sorting,
● opening and closing,
● clamping/pressing,
● rapid repetitive movements.
However, if the machine needs to handle multiple positions, change motion profiles based on the recipe, or precisely control speed, electric drives begin to offer the advantage.
When is an electric actuator the better choice?
An electric actuator is a good choice when the movement is not merely a simple extend-and-retract action, but a programmable part of the process.
It offers the greatest advantage in cases involving:
● multiple intermediate positions,
● precise stroke control,
● speed changes during motion,
● synchronization with other axes,
● automatic machine setting changes,
● elimination of hydraulics or pneumatics,
● the need for motion control via PLC.
However, selecting the right category of device is crucial.
For heavy-duty machines operating with high forces and demanding cycles, Tolomatic industrial electric actuators are the starting point. The product range covers everything from medium-load applications to solutions capable of handling extreme forces.
If a durable actuator is needed for harsh conditions but a force of 445 kN is not required, the RSA/RSA-HT series offers up to 58 kN and is available with ball or planetary screws, as well as an IP67 rating.
For intermittent motion, Concens linear actuators may be a better solution—especially when compact dimensions, 12/24 V DC power, or suitability for mobile systems are key factors.
Where are industrial electric actuators used?
Pressing, bending, and crimping
High-force actuators are of particular interest in this area. The RSX is designed for applications such as pressing, punching, riveting, crimping, tube bending, and test stands.
Valves and heavy-duty adjustment mechanisms
The RSA-HT series can be used for opening and closing large valves, forming, and other processes requiring significant force. Its design offers up to 58 kN of force and the option of using a planetary roller screw.
Packaging and dispensing machinery
Electric control allows for adjustments to position, speed, and stroke length whenever the product recipe changes. Tolomatic industrial actuators are used in operations such as product pushing and insertion into packaging.
Format adjustment
Guides, stops, or work elements can automatically move to a new position following a product changeover, thereby minimizing manual retooling.
Building automation and intermittent-duty mechanisms
Compact Concens drives are well-suited for adjusting dampers, flaps, slide gates, skylights, and other components requiring short-stroke movements. This specific group of actuators is designed for applications with a 10% duty cycle.
Mobile equipment and space-constrained installations
Thanks to its 12/24 V DC power supply, compact diameter, and compatibility with battery-powered controllers, the CON electric actuator is an excellent choice for mobile equipment and applications where space for the drive unit is limited.
Compact systems with network control
When communication and programmable positioning are required alongside motion, the ICON actuator integrates a controller, Modbus RTU via RS-485, and functions enabling the synchronization of up to eight drives.
How to select an actuator for a machine?
Selection should begin with process requirements rather than the type of drive itself.
The key parameters are:
1. Required force – including working load, friction, acceleration, and an appropriate safety margin.
2. Stroke – the full required travel distance plus mounting allowance.
3. Speed – critical for both process throughput and the capabilities of the screw mechanism used.
4. Duty cycle – a key factor when choosing between an industrial-grade solution for heavy-duty operation and a compact actuator for intermittent use.
5. Accuracy and number of positions – important if movement is not limited to just two end positions.
6. Environment – temperature, dust, humidity, washdown capability, and required IP rating.
7. Control – simple directional signal, external controller, or integrated PLC communication.
This is clearly illustrated by AMG’s product range: the RSX is designed for extreme loads and high duty cycles; the RSA-HT for demanding industrial applications; the CON for compact systems using an external controller; and the ICON for applications where integrating the drive directly with the control system is advantageous.
Electric, hydraulic, or pneumatic – the choice should be dictated by the process.
Hydraulics, pneumatics, and electric drives each have their own areas of superiority. Hydraulics remain a strong choice for extremely heavy loads, while pneumatics excel in simple, rapid point-to-point movements.
Electric actuators gain the advantage when movement needs to be treated as a programmable part of the process. The ability to control position, speed, and acceleration facilitates automation, recipe changes, and the reduction of mechanical changeovers.
However, selecting the right type of electric actuator is equally important. AMG offers industrial electric actuators for continuous operation and demanding processes, as well as linear actuators for intermittent movement.
These groups include everything from units capable of generating hundreds of kilonewtons of force to compact drives with integrated controllers.
Therefore, before selecting a solution, it is important to define not only the required force and stroke but also the speed, duty cycle, number of programmable positions, environmental conditions, and control method. Only with this information can one decide between electric, hydraulic, and pneumatic systems and select the appropriate electric actuator design.
FAQ
What is the difference between an electric actuator and a hydraulic actuator?
An electric actuator uses a motor and a screw mechanism to generate motion, whereas a hydraulic actuator uses pressurized fluid acting on a piston. Electric actuators facilitate the programming of positions, speeds, and motion profiles, while hydraulic systems are traditionally suited for applications requiring very high forces.
How does a double-acting pneumatic actuator work?
Compressed air is supplied alternately to both sides of the piston. Pressure in one chamber causes extension, while switching the valve directs pressure to the other chamber to force the return stroke.
What types of electric actuators are available?
Types include industrial screw actuators designed for heavy-duty, high-load applications and compact linear actuators intended for intermittent use. They also differ in terms of the screw type, motor, guidance system, and control method.
When is an electric actuator a better choice than a hydraulic or pneumatic one?
Primarily when the application requires programmable positions, precise motion control, variable speed profiles, easy PLC integration, or the elimination of hydraulic and pneumatic infrastructure.
Can an electric actuator replace a hydraulic one?
In many applications, yes. Examples include the RSX actuators offered by AMG, which provide maximum forces ranging from 89 to 294 kN. They were specifically designed as an electromechanical alternative to hydraulic systems.