AUMA SG2+MEC Seawater-Resistant Part-Turn Actuator
Overview
The AUMA SG2+MEC is AUMA’s “small” electric part-turn actuator range with separate MEC controls. The actuator housing is made entirely of bronze and all external screws are stainless steel, which AUMA states ensures complete resistance against seawater even over a longer time period. The MEC controls are housed separately in aluminium with AUMA powder coating for premium corrosion resistance. The actuators cover a torque range of 25 Nm to 500 Nm and are designed for open-close duty and positioning duty (classes A and B, short-time duty S2 – 15 min), with a variant for modulating duty, class C, S4 – 40 %.
In Oman and the GCC, Seven Star LLC proudly supplies the AUMA SG2+MEC to marine, offshore, desalination and coastal industrial customers in the Sultanate of Oman and across the GCC. A country with long coastlines, port complexes at Sohar, Salalah and Duqm and heavy dependence on seawater cooling and desalination has a natural need for valve actuators that withstand salt exposure. Seven Star LLC helps buyers choose between this separate-controls design and the integral-controls SGC and SGM ranges.
Operating Principle
The AUMA SG2+MEC turns a brushless variable-speed motor into a quarter-turn output through a compact gear stage, giving an operating time for 90 degrees between 4 s and 90 s and a swing angle between 82 and 98 degrees. Limit and torque seating are monitored by the actuator, and a handwheel allows manual operation. Because the motor is brushless and speed-controlled, the actuator can start and stop gently, and the speed can be matched to the valve and the process within the stated range.
The control intelligence is not in the actuator but in the separate MEC controls. All parameters are set directly at the MEC controls, which contain the switchgear, the power supply unit and the interface to the DCS. They automatically switch the actuator off when the valve end position is reached, when motor overheating is detected or when a torque overload occurs. The AUMA SG2+MEC concept therefore keeps electronics away from the harshest part of the installation, since the actuator can sit on a valve exposed to spray, bilge water or vibration while the controls are installed at a more sheltered position.
Engineering Design of the AUMA SG2+MEC
All housing components of the actuator are bronze and external screws are stainless steel, so no separate protective coating is needed for seawater resistance. The enclosure protection is IP67, the corrosion protection is KTL, and the ambient temperature range is −25 °C to +70 °C. AUMA notes shock-proof tests for the military shipbuilding industry, and the dimension documents for the range specifically address military shipbuilding versions with MEC 02.1 and MEC 03.1 controls for SG 04.2 to SG 10.2 sizes.
The MEC controls offer up to four binary inputs and outputs whose signal assignments can be configured. An option provides a 4 – 20 mA position feedback signal, and another provides an analogue input for a positioner. Local controls at the MEC are available as an option. The actuator is available with 1-phase AC supply versions in the electrical data documentation, and couplings for part-turn actuators are available with keyway, two-flat and square bores, so that the AUMA SG2+MEC can be fitted to the valve shaft in the same way as other AUMA part-turn drives.
Key Features
The AUMA SG2+MEC is built for corrosive, shock-exposed and marine service. Its main features are as follows.
- Bronze actuator housing and stainless steel external screws for complete seawater resistance.
- Torque range of 25 Nm to 500 Nm, with operating times for 90 degrees of 4 s to 90 s.
- Brushless, variable-speed motor with limit and torque seating.
- Open-close and positioning duty (classes A and B, S2 – 15 min) plus a modulating variant, class C, S4 – 40 %.
- Separate MEC controls containing switchgear, power supply and DCS interface, with automatic switch-off at end position, overheating or torque overload.
- Up to four configurable binary inputs and outputs, with optional 4 – 20 mA position feedback and analogue positioner input.
- Shock-proof tests for the military shipbuilding industry and a handwheel for manual operation.
- MEC housing in aluminium with AUMA powder coating for premium corrosion resistance.
Industrial Applications
The AUMA SG2+MEC is intended for valves exposed to seawater: seawater cooling circuits, ballast and bilge systems on vessels, fire-fighting and deluge valves, intake and outfall valves at desalination and power plants, and small valves on offshore platforms and jetties. The separate controls help when the valve is in a flooded space, a splash zone or an area with limited access, because the electronics can be installed in a more convenient and protected location, and the bronze housing resists the corrosive effects of salt water without maintenance of coatings.
In Oman and the GCC, Seven Star LLC supplies the AUMA SG2+MEC for projects in the Sultanate of Oman and the GCC, including ports, shipyards and coastal facilities in Sohar, Salalah, Duqm and Muscat. Because AUMA also supplies integral-control versions, our team can propose the SGC, SGCR, SGM or SGMR where compact all-in-one actuators are preferable, and the SG2+MEC where controls must be separated from the actuator. If the AUMA SG2+MEC is not the closest fit for a valve, see the AUMA SGC-SGCR, the AUMA SGM-SGMR or the AUMA SV and MEC for alternatives from the same AUMA family.
Technical Specifications
The following table summarises the key data published by AUMA for the AUMA SG2+MEC. Detailed information for SG 04.2 to SG 10.2 with MEC 03.1 is available in the technical data sheet linked on this page.
| Parameter | Specification |
|---|---|
| Model | SG2 (SG 04.2 – SG 10.2) with MEC controls |
| Duty type | Open-close and positioning duty, classes A and B, S2 – 15 min; modulating variant class C, S4 – 40 % |
| Torque range | 25 Nm – 500 Nm |
| Operating time for 90° | 4 s – 90 s |
| Swing angle | 82° – 98° |
| Enclosure protection | IP67 |
| Corrosion protection | KTL |
| Ambient temperature | −25 °C to +70 °C |
| Housing material | Bronze actuator housing; stainless steel external screws; aluminium MEC housing with powder coating |
| Motor | Brushless, variable speed |
| Controls interface | Up to 4 configurable binary inputs and outputs; optional 4 – 20 mA feedback; optional analogue positioner input |
| Manual operation | Handwheel |
Request a Quote for AUMA SG2+MEC
To request a quotation for the AUMA SG2+MEC, send us the valve type, torque, supply voltage, duty type and required signals. Seven Star LLC will reply with a formal RFQ response, availability and delivery information and the technical data sheet linked on this page. In Oman and the GCC, we supply the equipment on request, and our instrumentation division is available to answer marine and coastal application questions.
- Datasheet AUMA SG 04.2 - SG 10.2 with MEC 03.1 Technical Data Download
AUMA actuator and gearbox types
SA multi-turn actuators handle open-close duty on gate and globe valves, and SAR is the modulating version; the listing includes the SA 07.2, SA 10.2 and SA 25.1. SAEx and SAREx are the explosion-proof equivalents. Part-turn duty on ball and butterfly valves is covered by SQ and the modulating SQR, or by an SA actuator combined with a GS part-turn gearbox. LE linear thrust units convert multi-turn output to thrust, and GHT multi-turn gearboxes extend the torque range up to 120,000 Nm. PROFOX is the compact actuator line. Special items include the seawater-resistant SGM and SGMR part-turn actuators with bronze housings, the SVC and SVCR globe valve actuators and the FQM fail-safe unit. Integral controls come as AM or AC versions.Where AUMA electric actuators are used
AUMA actuators are found in water, power, oil and gas, marine and general industry. In practice that means isolation and control valves in water treatment and pumping stations, power plant steam and cooling systems, tank farms and pipelines, and sluice gates and dampers.Ordering AUMA actuators and parts: what we need
For a replacement send photos of the actuator, motor and controls nameplates: type, order number, serial number and wiring diagram number. For a new actuator we need:- valve type, required torque or thrust, and turns or stroke
- valve mounting flange and stem or shaft details
- output speed, duty (open-close or modulating)
- supply voltage and frequency, control signals or fieldbus
- enclosure protection, ambient temperature, Ex requirement
Browse AUMA products by category: Valve Actuator, Industrial Communications.

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