What is an Electric Valve Actuator: How It Works & How to Choose
Choosing the right electric actuator valve ensures efficiency and reliability in fluid control systems. Without a clear understanding of how an electric valve actuator works, its features, and its uses, selecting the best option can be challenging. This guide will explore what an electric actuator valve is, the key functions of electric valve actuators, their common uses across industries, important features to consider, and how to choose the right one for your specific needs. Let’s go!
What is an Electric Actuator Valve?
An electric actuator valve is a type of valve that uses an electric motor to control the opening and closing mechanism. It comes with 2 parts: an electric actuator and a valve. An electric actuator, at its core, converts electrical energy into mechanical movement. This is achieved through a system of gears and a motor that work together to physically change the position of the valve. The valve itself is a mechanical device designed to start, stop, or regulate the flow of substances through pipes or passageways in a system.
Terms like "motor valve" and "electric actuator valve" are often used interchangeably in the industry because electric actuators rely on electric motors for their operation. Essentially, when you hear about a valve being operated by an electric actuator, it means a valve being controlled by a motor.
Electric valve actuators are essential in applications where remote or automated control is needed, allowing valves in hard-to-reach or widely distributed locations to be controlled with ease, improvised safety, and efficiency. This makes them particularly valuable in industrial plants, pipelines, and large infrastructure projects, including water and wastewater treatment, HVAC systems, oil and gas operations, chemical processing, and the food and beverage industry.
Electric Actuator Valves We Offer
We offer 2 electric actuator series tailored for precise valve control. The MK Series (MK21–MK24) delivers powerful, stable quarter-turn actuation for demanding industrial tasks. The JS Series combines compact design with smart features like 100% duty cycle, manual override, and versatile voltage adaptation—ideal for efficient, cost-effective control in small valve applications.
We also offer electric actuator valves, also known as motor valves, including our trusted QUEEN Series and JS Series. These motorized valves can be customized with butterfly valves, 3-way ball valves, and threaded or flanged ball valves to suit your specific needs.
How to Choose an Electric Valve Actuator
Selecting the right electric valve actuator is essential for ensuring reliable and efficient valve operation. Several key factors must be considered, from torque and power requirements to environmental conditions. Here’s a guide to help you make the best choice based on your specific application.
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Torque and Power Requirements
The actuator needs enough power to open and close the valve efficiently. The breakaway torque (the force needed to initially move the valve) is usually higher than the running torque. If the actuator’s torque is too low, it won’t be able to operate the valve properly.
In addition to torque, you also need to consider the power source. Electric actuators can be DC (12V, 24V) or AC (24V, 110V, 220V, 380V, 440V), so make sure the voltage matches the power supply at your installation site.
Finally, before installing an actuator, it's important to confirm that the valve’s required torque is less than the actuator’s output torque. To ensure safe and reliable operation, you should apply a safety factor of 1.3 to the valve’s maximum torque. This means multiplying the valve’s maximum torque by 1.3 to determine the minimum torque the actuator should be able to provide.
For example, if a 5” valve has a maximum torque of 80 Nm, multiplying it by 1.3 gives 104 Nm. In this case, if the actuator’s output torque is 150 Nm, it is suitable for installation. However, if the actuator only provides 90 Nm, it would not be suitable.
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Valve Compatibility
Not all actuators fit all valves. To ensure proper installation, check if the actuator follows ISO 5211 mounting standards, which makes it easier to swap between different brands. Pay attention to the output drive and shaft/stem connection to the valve. Also, the flange type and bolt pattern—some actuators require specific flanges based on torque and size. If your valve has a unique or brand-specific interface, you may need an adapter or a custom mounting solution.
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Environmental and Safety Considerations
The actuator’s operating environment greatly influences its durability and performance. Factors to consider include:
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Temperature range: Ensure the actuator can function in extreme heat or cold if necessary.
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Ingress Protection (IP rating): Defines resistance to dust, water, and other hazards. For example, an IP54 rating provides dust protection and resistance to water splashes, while an IP67 rating offers full dust protection and immersion resistance.
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Hazardous environments: If the actuator will be used in areas with flammable gases or dust, check for ATEX certification, which ensures it is explosion-proof.
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Control Options
How do you want to control the actuator? Different actuators offer various control options based on application needs:
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On/Off Control (2-Point): The simplest type, where the actuator fully opens or closes the valve.
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3-Point Control: Allows for incremental adjustments between open and closed positions.
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Modulating Control (DPS – Digital Positioning System): Provides precise positioning anywhere between 0° and 90° for applications requiring variable flow rates.
If your system needs fine control over flow regulation—such as in chemical dosing or HVAC systems—modulating actuators are a better choice.
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Material
The actuator’s housing material should match the environmental demands, the fluid being controlled, and the system pressure of your application. Common materials include:
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Plastic: Lightweight and corrosion-resistant but less durable for heavy-duty use.
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Aluminum: Strong and heat-resistant, making it suitable for industrial environments.
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Stainless Steel: Used for highly corrosive environments, such as chemical plants.
How Does an Electric Valve Actuator Work?
Electric valve actuators work by converting electrical energy into mechanical motion to control a valve’s position. When the actuator receives an electric signal, the motor activates, generating rotational movement. This motion passes through a gearbox, which adjusts the torque and speed to match the valve’s operational requirements. The processed mechanical force then moves the valve into the desired position—fully open, fully closed, or partially open for precise flow regulation.
To ensure accuracy, sensors would monitor the valve's position and the applied torque throughout the process. These sensors provide continuous feedback to the control system, helping maintain reliable and efficient operation.
Types of Motion in Electric Actuators
Electric valve actuators operate in two primary motion types, depending on the different valve designs:
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Rotary (Quarter-Turn) Actuators: These actuators are used for ball, butterfly, and plug valves, which require a 90-degree rotation to switch between open and closed positions. They provide fast and efficient valve operation, making them ideal for automated systems.
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Linear Actuators: Designed for gate and globe valves, these actuators move the valve stem in a straight line to control flow. They are typically used in applications requiring more precise throttling or when a greater force is needed to operate the valve.
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Spring Return Actuators: Use a spring and rack mechanism to ensure fail-safe operation. When power is supplied, the spring compresses and stores energy. If the power supply fails, the spring releases its stored energy to drive the valve or damper to a pre-set safe position, without the need for any external power source.
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Multi-turn Electric Actuators: Built for valves that require more than one full turn to operate, such as large gate or globe valves. They provide high torque over multiple rotations, making them suitable for heavy-duty operations or valves with a long stem travel.
Features of Electric Valve Actuators
To ensure consistent performance and prevent disruptions, an electric valve actuator comes with these reliability features:
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Fail-Safe Mechanisms
Fail-safe features ensure that valves move to a predetermined safe position (open or closed) in the event of power loss or system failure. This is crucial in preventing accidents and maintaining system integrity. Fail-safe mechanisms can be implemented using:
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Spring Return Systems: Utilize mechanical springs to drive the valve to its safe position upon power loss.
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Battery Backup Systems: Employ rechargeable batteries to provide the necessary power to move the valve to its safe position during an outage.
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Manual Override
A manual override allows operators to manually control the valve in situations where the actuator is non-functional or during power outages. This feature typically involves a mechanical handwheel or handle that enables manual positioning of the valve, ensuring continued operation or safe shutdown when automatic control is unavailable.
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Limit Switches
Limit switches are electro-mechanical components that detect and signal when a valve has reached its fully open or fully closed position. They consist of cams that move with the actuator, cutting off electrical power once the desired position is achieved. This prevents over-travel and potential damage to the valve or actuator. Some actuators feature adjustable limit switch cams, allowing customization of end positions to specific operational requirements.
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Torque Sensors
Torque sensors monitor the force exerted by the actuator to operate the valve. If the torque exceeds predefined limits—due to obstructions or valve seizing—the actuator can halt operation to prevent damage. This protective feature ensures that both the actuator and valve remain within safe operational parameters.
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Duty Cycle
The duty cycle defines the proportion of time an actuator can operate within a given period without overheating. It's expressed as a percentage and calculated by dividing the operating time by the total cycle time (operating time plus rest time). For example, an actuator that operates for 30 seconds and then rests for 30 seconds has a 50% duty cycle.
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Position Feedback with Potentionmeter
A potentiometer provides a feedback signal that indicates the current position or opening percentage of the valve. This allows control systems or operators to monitor how far the valve is open or closed in real time, improving accuracy and automation in flow control systems.
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Modulating Control Unit
The modulating control unit enables the actuator to respond to input signals that control how much the valve opens. It also sends back a feedback signal to indicate the valve’s current position. This is useful for precise flow regulation. Both voltage and current signals can be used for input and output. Common voltage signals include 1–5V, 0–5V, 2–10V, and 0–10V, while standard current signals include 4–20mA and 0–20mA.
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Internal Heater
An internal heater raises the temperature inside the actuator to prevent the lubricating grease from solidifying in cold environments. It also helps keep the interior dry by reducing humidity, which protects the actuator from moisture-related failures or corrosion—especially in outdoor or harsh settings.
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Motor with Thermal Protection
The motor inside the actuator includes a built-in thermal protection system. This feature prevents the motor from overheating by automatically shutting it down or adjusting its operation if the temperature gets too high, helping to avoid damage or burnout.
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Local Control Unit
The local control unit allows operators to choose between local and remote control modes. When in local mode, the actuator can be directly operated on-site using a selector switch with options like Open, Stop, and Close. This is especially useful for maintenance or emergency manual control.
Benefits of Electric Valve Actuators
Whether you’re working with water systems, chemical processes, or HVAC setups, these electric actuators provide efficiency, precision, and reliability. Let’s break down why they stand out:
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Remote Operation
With electric actuators, remote operation is a game-changer. They can be controlled and monitored from a centralized system, allowing operators to check performance and make adjustments without physically accessing the valve. This is especially useful for large industrial plants, hazardous environments, or hard-to-reach installations where on-site intervention is difficult or unsafe.
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Precise Control
Electric actuators allow for precise valve movement, which is crucial for controlling flow rates in automated systems. They can be programmed to open or close at specific positions and speeds, ensuring smooth operation.
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Low Maintenance
Compared to pneumatic or hydraulic systems, electric actuators have fewer moving parts, which means less wear and tear over time. They don’t require lubricants, eliminating contamination risks and reducing maintenance costs. Once installed, they can run for long periods with minimal upkeep, making them a cost-effective choice for long-term use.
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Energy Efficiency
One of the biggest perks of electric valve actuators is their energy efficiency. Unlike pneumatic or hydraulic actuators, they consume significantly less energy, making them ideal for applications where energy conservation is a priority. Some models even feature variable speed drives, which further optimize energy use by adjusting power output based on demand.
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Clean and Quiet Operation
Unlike pneumatic and hydraulic actuators, which rely on air compressors or fluid pumps, electric actuators operate cleanly and quietly. There’s no risk of leaks from hydraulic fluid or compressed air, and they generate much less noise, making them ideal for environments where cleanliness and noise reduction matter.
KUHNWAY Brings You the Best Solutions for Valves with Electric Actuators
Electric valve actuators bring efficiency, accuracy, and reliability to automated systems. Whether you’re looking to reduce energy costs, improve control precision, or minimize maintenance, they offer a powerful solution.
Looking for reliable, high-performance electric actuators and actuator motorized valves? KUHNWAY delivers efficiency, precision, and durability for automated systems. Whether you need a complete electric actuator valve or a standalone electric actuator, we provide cutting-edge technology, superior quality, and expert support.
With 30+ years of experience, we’re committed to optimizing your operations while reducing energy costs and maintenance. Join countless satisfied customers who trust KUHNWAY for seamless automation. Upgrade your system today—contact us to find the perfect solution tailored to your needs!