How does an electric ball valve work?

An electric motor drives the ball shaft via a gear train. In the open position the bore of the ball aligns with the pipeline: pressure drop is minimal and flow is unrestricted. In the closed position the bore is perpendicular to the pipeline and the passage is fully blocked. Limit switches register both end positions and send an open/close feedback signal to the control system. A position indicator on the actuator also shows the status locally. In modulating configurations the actuator positions the ball continuously between 0 and 100%, driven by an analogue signal or fieldbus protocol.

On/off, 3-point or modulating control?

The choice of control type determines the accuracy and complexity of the regulation. Three variants are available:

• On/off (2-point): the actuator switches fully open or fully closed. Most reliable, lowest purchase cost. Suitable for on/off automation of utility lines and process water.
• 3-point (floating): two direction signals drive the actuator step by step open or closed. Simple integration without position feedback.
• Modulating (analogue or fieldbus): a 0–10 V or 4–20 mA signal drives the actuator to a proportional position. Precise flow or pressure control. Via AS-interface, direct integration with PLC or DCS is possible. Ebora supplies its own AS-i card for the EBNE actuators.

Choose on/off for straightforward automation, 3-point when no analogue signal is available but stepwise control is required, and modulating when precise flow or pressure regulation is needed.

Selecting the supply voltage

The most common voltages are 24 V DC/AC and 230 V AC. The choice depends on your control cabinet, inrush current and local safety regulations. In industrial environments with PLC control, 24 V DC is often preferred for its low voltage and simple wiring. For standalone applications or building installations, 230 V AC is practical as no power conversion is required. Ebora also supplies versions at 12 V DC, 110 V AC and 400 V AC. State the available supply voltage in your enquiry.

IP rating and environmental protection

The IP rating defines the actuator's protection against moisture and dust. The three most commonly applied ratings are:

• IP65: splash-proof, suitable for indoor applications with a risk of washdown
• IP67: submersible to 1 m for 30 minutes, suitable for outdoor installations
• IP68: continuous submersion, suitable for washdown zones and underground applications

For applications with large temperature fluctuations, consider an anti-condensation heating element in the actuator to prevent moisture build-up.

Fail-safe: battery, supercapacitor or spring return?

On power failure, a fail-safe actuator must move the ball valve to a safe position — open or closed, depending on your process design. Two methods are available:

• Battery or supercapacitor backup: the actuator stores energy and drives to the safe position on power loss. Cost-effective, compact and reliable for most applications.
• Spring return: a mechanical spring moves the actuator directly to the safe position, without reliance on stored energy. Highly effective, but generally more expensive to purchase.

Select based on required response time, budget and maintenance preference. Ebora advises on the most suitable method per application.

Sizing torque and duty cycle correctly

Start with the required torque of the ball valve under your process conditions: distinguish between break torque, run torque and seat torque. Correct for medium viscosity, pressure, temperature and potential wear. Then apply a safety margin of at least 25–30% and select an actuator with sufficient torque reserve. Also consider the duty cycle (ED%): an actuator that switches frequently at high torque may overheat thermally if the ED% is too low. Fast electric versions achieve cycle times of approximately one second per stroke — also check the peak current and supply capacity of your installation.

Plastic or aluminium actuator?

Plastic actuators are lighter and corrosion-resistant, making them particularly suitable in combination with plastic ball valves in PVC, PP or PVDF. The lower weight reduces mechanical load on the valve connection. Aluminium actuators are more robust and better suited to mechanical load and high ambient temperatures. They are used with metal ball valves in higher pressure and temperature classes. In both cases, coupling is via ISO 5211; Ebora supplies a bracket or adapter where needed for safe and accurate mounting.

Application guide

Applications by sector

Electric ball valves are widely used wherever reliable, automated shut-off or control is required without a compressed air supply:

• Process water and utilities: frequent switching cycles in water treatment, cooling water and compressed air installations
• HVAC: zone and mixing control with modulating actuation via 0–10 V or 4–20 mA
• Chemical and tank storage: controlled remote operation with aggressive or hazardous media
• Food and pharmaceutical industry: stainless steel versions with hygienic seals and traceability documentation
• Plastic pipework: lightweight plastic actuator limits mechanical load on the valve connection

Electric actuation is particularly suitable when compressed air is not available or when precise positioning via PLC or DCS is required. For applications with high switching speeds or in hazardous areas, also compare the pneumatic ball valves. If you want to operate manually for now with preparation for future automation, see the ball valve with bare shaft.

Valve Automation Centre

Ebora assembles, configures and tests electric ball valves in its own Valve Automation Centre. You receive a complete assembly — ball valve, actuator, bracketry and coupling — set up to your specifications. Test reports and traceability documentation are available on request. This means no assembly is required on your end, and you can be confident the combination functions correctly before commissioning. View the complete range of ball valves for all configurations and materials.

Request advice or a quotation

Provide the following data with your enquiry: medium, pressure, temperature, control type (on/off, 3-point or modulating), supply voltage, required IP rating and whether fail-safe is needed. Also state the ball valve body material and connection type (BSP/NPT, weld or flange). We will size the actuator, calculate the torque including margin and deliver the complete assembly fully tested.

Select the right electric ball valve based on your process data or request a quotation via the contact page.

Frequently asked questions about electric ball valves

What is the difference between an electric and a pneumatic ball valve?

An electric ball valve only requires a supply voltage and is therefore easy to apply where no compressed air is available. Pneumatic actuators generally switch faster and are more suitable in hazardous areas, but require a compressed air supply and additional safety components. The choice depends on your infrastructure, required switching speed and area classification.

Can I automate an existing ball valve electrically at a later stage?

This is possible if the ball valve has a bare shaft conforming to ISO 5211. The actuator is then mounted directly via a bracket and coupling. If your valve does not yet have a bare shaft, you can order a ball valve with bare shaft prepared for future automation. Ebora advises which actuator suits the existing torque requirements and connection dimensions.

How do I connect an electric ball valve to my PLC or DCS?

For on/off versions, connect two control wires to the digital output of your PLC and link the feedback contacts to digital inputs. Modulating versions receive an analogue signal (0–10 V or 4–20 mA) and return a position feedback signal. Via AS-interface, multiple actuators can be integrated on a single two-wire bus. Ebora supplies its own AS-i card for the EBNE actuators.

Which actuator is suitable for a plastic ball valve?

For plastic ball valves in PVC, PP or PVDF, select a plastic actuator. The lower weight reduces mechanical load on the valve connection and limits the risk of cracking at the connection point. Coupling is via ISO 5211; Ebora supplies a bracket or adapter where needed for correct mounting.