AUMA SAR-UW Underwater Modulating Multi-Turn Actuator

Overview

AUMA SAR-UW is the modulating-duty member of AUMA’s underwater multi-turn actuator family. Where the open-close AUMA SA-UW simply drives a gate from one end position to the other, the AUMA SAR-UW is engineered to hold a submerged valve at any intermediate position and to follow a control signal continuously, with a torque range of 15 Nm to 4,000 Nm and a modulating torque range of 15 Nm to 1,600 Nm. That makes it the right drive for submerged flow-control and level-control gates that must be positioned, not just opened and closed.

In Oman and the GCC, Seven Star LLC supplies the AUMA SAR-UW to desalination plants, water authorities, marine and port operators and EPC contractors across the Sultanate of Oman and the GCC. Because modulating duty puts far more stress on an actuator than occasional switching, correct sizing is critical, and our Muscat instrumentation team reviews the required modulating torque, starts per hour and head of water with you before any order is placed.

Working Principle of the AUMA SAR-UW

The AUMA SAR-UW uses a 3-phase AC asynchronous motor designed for intermittent duty S4-25 % and S4-50 % (class C according to EN ISO 22153) driving a self-locking gear train. A set-point from the control system is compared with the actual valve position reported by the actuator, and the AC controls issue short motor pulses to correct the deviation. Pulse durations are short and well defined, in the order of 60 to 275 ms depending on size and speed, which is what allows fine positioning of a heavy gate without hunting.

The immersed parts follow the same philosophy as the rest of the UW series: a double-sealed terminal compartment, double-sealed cable glands, inner seals on every cover and a solid stainless steel output shaft protect the motor and gearing, while the magnetic limit and torque transmitter (MWG) senses position and torque without wear-prone mechanical switches. The AC actuator controls sit on a wall bracket outside the water and are connected through a purpose-built cable set, so positioner electronics, fieldbus interfaces and diagnostics remain dry and serviceable.

Engineering Design of the AUMA SAR-UW

The AUMA SAR-UW is available in the sizes SAR 07.2-UW to SAR 16.2-UW as well as SAR 25.1-UW and SAR 30.1-UW, with output speeds of 4 to 90 rpm at 50 Hz. The small and medium frame sizes support up to 1,200 starts per hour (up to 1,500 on selected variants), while the large SAR 25.1-UW and SAR 30.1-UW are rated for up to 300 starts per hour. Valve attachments follow EN ISO 5210, F07 to F30, with DIN 3210 options, and output drive type B1 is standard.

Protection is IP68-C15 for a head of water of 15 m, with IP68-C60 for 60 m as an option. The outer parts are aluminium-free and finished in KX-G with a two-layer powder coating plus wet paint, which AUMA qualifies for freshwater (Im1), seawater (Im2) and seafloor (Im3) applications. Operating temperature is –30 °C to +70 °C, and a handwheel for manual setting is available for the small and medium frame sizes.

Key Features

The following characteristics define the AUMA SAR-UW for submerged modulating service:

• Modulating duty S4-25 % and S4-50 % in class C ensures the actuator is rated for continuous positioning rather than occasional switching.
• A torque range of 15 Nm to 4,000 Nm, with a modulating torque range of 15 Nm to 1,600 Nm, covers a wide spread of gate and valve sizes.
• Short, repeatable pulse durations give fine position resolution for heavy submerged gates.
• Continuous underwater use is certified to IP68-C15 as standard, with a 60 m head-of-water option.
• Double-sealed cable glands and a doubly sealed terminal compartment keep water out of the actuator even at the cable entry.
• The non-intrusive magnetic limit and torque transmitter removes mechanical switches from the underwater housing.
• KX-G corrosion protection with aluminium-free outer parts suits freshwater, seawater and seafloor conditions.
• AC actuator controls on a wall bracket provide positioner, diagnostics and fieldbus integration in a dry location.

Industrial Applications

The AUMA SAR-UW is used where a submerged valve or gate has to regulate rather than isolate: level control gates in water intake channels, flow-regulation gates at the head of cooling-water circuits, adjustable weirs and sluice gates in irrigation and flood-protection structures, and bypass or dosing gates in treatment works. In the Sultanate of Oman this includes seawater intake structures serving the coastal desalination and power plants near Sohar, Barka and Salalah, and the falaj-fed and wadi-management structures that regulate seasonal flow.

In Oman and the GCC, Seven Star LLC supplies the AUMA SAR-UW together with the matching AC controls, cable set and documentation. If a submerged valve only needs to open and close, we will point you to the open-close AUMA SA-UW, which avoids paying for modulating capability you do not need; if the process demands positioning, our team will confirm that the modulating torque and starts-per-hour rating of the chosen SAR-UW size match the control loop. If the AUMA SAR-UW is not the closest fit for a valve, see the AUMA SA-UW, the AUMA SAR 14.1 multi-turn actuator or the AUMA MATIC AM/AC integral actuator controls for alternatives from the same AUMA family.

Technical Specifications

The table collects the main data of the AUMA SAR-UW from the AUMA product page and technical data sheet PR01425 (SAR 07.2-UW to SAR 16.2-UW) and its companion sheet for SAR 25.1-UW and SAR 30.1-UW.

Request a Quote for AUMA SAR-UW

To request a quotation for the AUMA SAR-UW, send Seven Star LLC your required modulating torque, positioning accuracy, starts per hour, head of water and cable length. Our instrumentation division will return an RFQ response with the correct size, controls and cable set, and you can download the technical datasheet from this page. In Oman and the GCC, we supply the product with local support, and can advise on lead times and availability.