AUMA SA and GHT Multi-Turn Actuator with Worm Gearbox

Overview

AUMA SA and GHT is the heavy-duty end of AUMA’s multi-turn range: a large SA multi-turn actuator combined with a GHT worm gearbox to deliver valve torques from 32,000 Nm up to 120,000 Nm. Where AUMA’s SA actuators on their own cover up to 32,000 Nm, the AUMA SA and GHT combination extends that reach to the giant gate valves, sluice gates, weirs, louvre dampers, stack dampers and diverters found in major water, power and industrial infrastructure, and keeps the same SA controls and commissioning philosophy.

In Oman and the GCC, Seven Star LLC supplies the AUMA SA and GHT to dam and canal operators, desalination plants, power stations and heavy industry across the Sultanate of Oman and the wider GCC. Combinations at this size need careful engineering of torque, running time, flange and weight, so our Muscat instrumentation team works with you and AUMA from the first valve data sheet through to commissioning documentation.

Working Principle of the AUMA SA and GHT

The AUMA SA and GHT works through a worm gear stage: the SA actuator turns a hardened worm shaft, which drives a bronze worm wheel on the output side. Reduction ratios of roughly 10:1 to 20.5:1 slow the actuator’s 4 to 90 rpm output speeds to between about 0.3 and 9 rpm at the valve stem on the GHT .3 series, and the same ratio multiplies torque. AUMA publishes a conversion factor for each ratio, between about 8 and 16.4, which is used to calculate the required actuator input torque from the maximum output torque, and a verification of the actuator sizing is required for running times above two minutes and for high output speeds.

The GHT gearbox is not self-locking, which is why AUMA specifies suitable SA actuators for each ratio and notes where the actuator itself is not self-locking at high output speeds. The actuator’s torque and limit switching continue to protect the valve, with the gear factor applied during commissioning. The result is a very high-torque, low-speed drive for valves that are physically large and slow by nature, with precise end-position and torque control.

Engineering Design of the AUMA SA and GHT

The GHT range comprises the GHT 320.3, GHT 500.3, GHT 800.3 and GHT 1200.3, with maximum output torques of 32,000, 50,000, 80,000 and 120,000 Nm respectively, together with the GHT 360.2 for 80,000 Nm. Output flanges go up to F48 and F60 to EN ISO 5210, input shaft diameters range from 60 mm to 100 mm, and gearbox weights run from about 477 kg for the GHT 320.3 to about 1,280 kg for the GHT 1200.3. The worm wheel is made of bronze, and the input shaft is cylindrical with a parallel key to DIN 6885-1.

The gearbox is rated for open-close duty S2-15 min in classes A and B in accordance with EN ISO 22109 and has a maximum input speed of 90 rpm. Enclosure protection is IP68 for the GHT .3 series (IP67 for the GHT 360.2), corrosion protection is class KN with a high-quality coating, and the gearbox can be mounted in any position. Mounting flanges for the actuator range from F25 to F40, depending on the gearbox, and the combination is documented as suitable for an ambient range of –30 °C to +70 °C, with gearbox-only data from –40 °C to +80 °C.

Key Features

The following characteristics define the AUMA SA and GHT combination:

• Output torques from 32,000 Nm up to 120,000 Nm extend the SA actuator range to the largest industrial valves and gates.
• A bronze worm wheel and hardened worm shaft provide high torque transmission with a robust, proven gear design.
• Four main gearbox sizes (GHT 320.3 to GHT 1200.3) plus the GHT 360.2 allow close matching of torque to the valve.
• Two or three ratios per size, from about 10:1 to 20.5:1, let output speed be tailored to valve travel and running time.
• Direct combination with SA 25.1 to SA 40.1 actuators keeps standard AUMA controls, plug/socket connection and spares.
• IP67/IP68 enclosure protection and KN corrosion protection suit outdoor and plant environments.
• Valve attachment to EN ISO 5210 up to F48 and F60 suits large gate and damper drives.
• Electrical connection through the AUMA plug/socket connector, with terminals as an alternative, and cable entries in several versions.

Industrial Applications

The AUMA SA and GHT is used on gate valves and sluice gates of very large diameter, on weirs and diverters in irrigation and flood-protection works, on louvre and stack dampers in power stations and cement or metals plants, and on large special valves in cooling-water intakes. In these installations the valve moves slowly, the torque is very high, and the actuator must provide reliable torque and position protection over many years of infrequent operation.

In the Sultanate of Oman, candidate sites include the large water intake and outfall structures of coastal desalination and power plants near Sohar, Barka and Salalah, the dampers and diverters of heavy-industry plants in Sohar and Duqm, and flood-control and wadi-management gates. In Oman and the GCC, Seven Star LLC supplies the AUMA SA and GHT with full application engineering, including torque and running-time checks, flange and weight confirmation, and coordination with the valve manufacturer. When reviewing the AUMA SA and GHT against the rest of the AUMA range, engineers often also look at the AUMA GHT, the AUMA SA and GK and the AUMA GST spur gearbox.

Technical Specifications

The table summarises the main data of the AUMA SA and GHT combination from the AUMA product page and the technical data sheet for GHT 320.3 to GHT 1200.3.

Request a Quote for AUMA SA and GHT

To request a quotation for the AUMA SA and GHT, send Seven Star LLC the valve type, maximum output torque, required operating time, flange size and installation drawings. Our instrumentation division will coordinate sizing with AUMA and provide an RFQ response, and the technical datasheet can be downloaded from this page. In Oman and the GCC, we supply the product with manufacturer documentation and local support, and can advise on lead times for these made-to-order combinations.