Multi-Turn Electric Actuators

A multi-turn electric actuator is an actuator whose output shaft rotates through tens of revolutions and transmits not only torque to the valve, but also axial thrust. These actuators operate heavy gate valves, globe valves and high-pressure valves where high force, positioning accuracy and long service life are required. “ZAVOD “ARMA” LLC (Kyiv) is the official exclusive representative of “SCHIEBEL ANTRIEBSTECHNIK GMBH” in Ukraine. We select each multi-turn electric actuator for the specific valve and site conditions and support the project through commissioning.

What Is a Multi-Turn Electric Actuator?

By design, multi-turn electric actuators consist of an electric motor, a multi-stage gearbox, a control unit, limit and torque switches, a manual override handwheel and a position indicator. Unlike quarter-turn actuators, which rotate the shaft through only 90°, a multi-turn actuator makes as many revolutions as required to fully raise the gate valve stem or move the valve stem, from several to several hundred turns.

The connection to the valve is standardized in accordance with ISO 5210. For gate valves with a rising stem, an output drive form A with a thrust bearing is used. It absorbs the axial load and converts it into smooth stem movement. This is a fundamental distinction: a multi-turn actuator operates not only by transmitting torque, but also by generating thrust.

In simple terms, a multi-turn model is used wherever the valve requires many turns for full travel and the actuator must provide substantial force and accurate positioning.

Technical Specifications

The key characteristic of this actuator class is the combination of high torque and controlled axial thrust.

Parameter	Typical Value
Torque	From tens to several thousand Nm, depending on the series
Number of output shaft revolutions for full travel	From several to several hundred
Axial thrust, output drive form A	Up to tens of tonnes
Power supply	230 V, 380 V or 24 V DC
Enclosure protection	IP67; IP68 for floodable chambers
Design	General industrial or explosion-proof (Ex)

Exact values depend on the SCHIEBEL model and series. The required range is selected according to the actual valve torque with an appropriate engineering margin.

Applications of Multi-Turn Electric Actuators

Multi-turn actuators are the standard solution for heavy-duty valves in four key application areas:

• Electric actuators for gate valves. Wedge gate valves, knife gate valves and parallel slide gate valves are widely used on trunk pipelines, pumping stations and municipal water systems. The valve stem must rotate through tens of turns to move the gate fully clear of the flow passage. Heavy gate valves of DN 300 and above require models with increased torque, from 500 to 32,000 Nm.
• Electric actuators for globe valves. This includes shut-off, control and combined shut-off-and-control globe valves of various types. Accurate stem positioning and force control are critical. Excessive closing force can damage the valve seat and lead to costly maintenance.
• Electric actuators for high-pressure valves. Oil and gas facilities, power plants, combined heat and power plants and nuclear power plants use valves operating at pressures of tens or hundreds of bar. An actuator for such valves requires a reinforced gearbox, a sensitive torque switch and a confirmed service life.
• Electric actuators for trunk pipelines. Trunk oil, gas and product pipelines, as well as large-diameter water pipelines, use actuators on line valves that isolate the flow under operating pressure. Explosion-proof versions with ATEX/IECEx marking are often required, together with confirmed conformity to the Technical Regulation on Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres.

Additional applications include nuclear power generation, including auxiliary circuits and service water systems; the chemical and petrochemical industries, including aggressive media and corrosion-resistant enclosures; and thermal power generation, including high-pressure steam valves.

Advantages of Multi-Turn Electric Actuators

High torque. The available model range covers torque values from 10 to 32,000 Nm and above. This makes it possible to select an actuator for virtually any heavy gate valve or globe valve with a 25–30% margin, extending service life and preventing operation at the limit.
Resistance to high loads. The multi-stage gearbox and reinforced output shaft are designed for repeated starting torque and operation at rated load throughout the actuator’s service life. This is essential on trunk pipelines and high-pressure valves operating under demanding duty conditions.
Accurate positioning. Modern models maintain the valve stem position with an accuracy of up to 1% of full travel. This is important for control applications, such as accurate flow dosing on process lines or gradual opening of a gate valve during start-up.
Multiple operating modes. The actuator can operate in a simple two-position mode, open/close/stop, or in modulating duty using a 4–20 mA analogue signal or digital fieldbus communication. Switching between modes is performed by software and does not require equipment replacement.
Reliability over tens of thousands of cycles. European-made industrial models are designed for 10,000–25,000 operating cycles. Under the typical duty of trunk pipeline valves, this corresponds to 15–25 years of service. The rated service life is confirmed by the equipment passport and the manufacturer’s test reports.
Overload protection. Torque switches automatically disconnect power when the preset torque is exceeded, protecting both the valve and the gearbox. Motor thermal protection is provided as standard.
Operation in demanding environments. Explosion-proof versions, including Ex d and Ex de, enclosure protection up to IP67/IP68, an operating temperature range from -60 °C to +80 °C, and versions for marine atmospheres are available within the same product range.
Manual override. In the event of a power failure, the actuator can be operated mechanically by handwheel. This is a mandatory function for critical valves.

How to Select a Multi-Turn Electric Actuator

Selection is based on seven parameters:

1. Valve torque. Use the actual opening and closing torque of the gate valve or globe valve and add a margin of 25–30%. This is the main selection parameter and determines the entire actuator configuration.
2. Number of output shaft revolutions. A specific number of stem turns is required for full valve opening. This determines the gearbox selection.
3. Rotational speed. The higher the actuator speed, the shorter the full-stroke operating time. Emergency isolation may require only several seconds, while modulating applications may require one minute or more.
4. Connection type. The ISO 5210 mounting flange, type A, B1, B2, B3, B4 or C, must match the valve. Adapter flanges can be used where the interfaces do not match, but they add additional components and reduce overall reliability.
5. Power supply. Three-phase 380 V is used for most industrial models; single-phase 230 V is used for smaller actuators; 24 V DC is used in systems with battery-backed power.
6. Control type. Discrete open/close/stop control is the simplest arrangement; 4–20 mA analogue control is used for modulating applications; Modbus RTU/TCP, PROFIBUS DP and HART are used for integration into industrial control systems with remote valve status indication.
7. Operating conditions. Consider the ambient temperature range, required IP protection, the presence of a potentially explosive atmosphere, ATEX/IECEx requirements and corrosive agents. Oil and gas and nuclear applications are subject to additional industry-specific requirements.

If any parameter is uncertain, send us the Technical Questionnaire or the requirements for the actuator’s technical and quality characteristics. Our engineer will prepare a technically substantiated selection as quickly as possible.

Buy Multi-Turn Electric Actuators in Ukraine

The website presents multi-turn electric actuators for shut-off and control valves from the Austrian brand SCHIEBEL, one of the recognized suppliers of actuators for oil and gas infrastructure and nuclear power facilities.
Your order includes:

• Official supply with a complete documentation package: Type Examination Certificate, Notification of Conformity to Type Based on Product Quality Assurance, Declaration of Conformity for explosion-proof models, Operating Instructions, and other required documents.
• Engineering support before and after order placement, including assistance with parameter setting, integration into industrial control systems and coordination of control protocols.
• Manufacturer’s warranty for the full period specified in the equipment passport.
• Fast delivery throughout Ukraine.

Prices for multi-turn electric actuators depend on the required torque, design, general industrial or Ex, and the availability of digital communication interfaces. The exact price for your application is calculated after receipt of the input data. A commercial proposal is prepared as quickly as possible.

Why Customers Choose Us

• Engineering selection, not catalogue selection. Our engineer analyses the Technical Questionnaire, checks compatibility with the valve and proposes a model with a clear technical justification.
• A proven manufacturer. Our portfolio includes SCHIEBEL multi-turn electric actuators with confirmed quality and a complete set of certificates for the Ukrainian market.
• Support at every stage. We assist with parameterization, adjustment of torque and limit switches and integration into the plant control system. We do not leave the customer alone with the equipment after delivery.
• Delivery throughout Ukraine. Delivery arrangements are agreed individually: collection from the warehouse, shipment by the customer’s preferred carrier, or transport by our vehicle for oversized items.
• Complete documentation. Equipment passports, certificates, technical specifications and test reports are supplied for each unit of equipment, including documents required for tenders and project deliveries.

FAQ

What is a multi-turn electric actuator used for?

A multi-turn electric actuator is used for automatic control of valves whose closure member, such as a gate valve wedge or valve stem, must travel through a long stroke involving tens or hundreds of stem revolutions. Typical applications include trunk pipeline gate valves, heavy globe valves and stem-operated control valves. The actuator replaces the manual handwheel, enables remote control from the control room and integrates the valve into the plant’s industrial control system.

How should the required torque be selected?

Use the actual opening and closing torque specified in the valve passport and add a margin of 25–30%. For example, if the specified gate valve torque is 1,000 Nm, select an actuator rated at 1,250–1,300 Nm. This margin allows for increased torque caused by stem seizure, deposits on the seat or thermal deformation. Selecting an actuator without sufficient margin is unsafe: the actuator will operate at its limit, the torque switch may trip prematurely and the gearbox service life will be significantly reduced.

Is delivery available throughout Ukraine?

Yes. We ship equipment throughout Ukraine. Smaller models are sent by transport companies such as Nova Poshta or Delivery, while oversized items are transported by road according to an agreed schedule.

Are explosion-proof versions available?

Yes. Multi-turn electric actuators in Ex d, Ex de and Ex e versions are available from stock or to order, with ATEX/IECEx markings for operation in Zones 1 and 2 for gas and Zones 21 and 22 for dust. The equipment complies with the Technical Regulation on Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres, the Ukrainian equivalent of the European ATEX Directive.

What service life are multi-turn actuators designed for?

European-made industrial models are designed for 10,000–25,000 operating cycles when used correctly. For the typical duty of trunk pipeline valves, involving only several cycles per year, this corresponds to 15–25 years of service. For control valves with intensive operation, the service life is shorter, so the expected number of cycles per year must be considered during selection.

Can an actuator be supplied for a non-standard valve?

Yes. If the valve has a non-standard mounting interface, specific torque requirements or special operating conditions such as high temperature, aggressive media or a marine atmosphere, we coordinate the configuration with the manufacturer. Where necessary, we select an adapter flange or order a special actuator version.

Need Help Selecting a Multi-Turn Electric Actuator?

Submit a request through the website or call us. Our engineer will answer your questions, request the valve parameters and prepare a commercial proposal with technical justification.