AUMA GS Part-Turn (Quarter-Turn) Gear Boxes
Overview: High-Torque Solution for Large Part-Turn Valves
The AUMA GS Part-Turn Gearbox is a worm gear reducer used for the operation of part-turn and special valves – butterfly valves, ball valves, dampers, and flue gas dampers – where torque requirements exceed what the standard SQ part-turn actuator range can deliver on its own. Combined with an AUMA SA multi-turn actuator, the GS gearbox forms a high-torque electric part-turn actuator reaching nominal torques up to 675,000 Nm, complementing the SQ range (limited to 2,400 Nm) for the largest part-turn valve applications.
As a trusted supplier of AUMA valve gearboxes, Seven Star LLC sources and supplies the GS part-turn gearbox to power plants, large water infrastructure projects, and heavy process industries across Oman and the wider GCC. Because large-diameter butterfly and ball valves in major pipelines and dampers demand torque levels far beyond typical part-turn actuators, Seven Star LLC helps engineering teams specify the correct GS gearbox size and reduction ratio for these demanding applications.
Working Principle: Worm Gear Torque Multiplication with Self-Locking
The GS gearbox uses a worm wheel and worm shaft as its core components, providing high gear reduction within a single gear stage while delivering an important self-locking effect that prevents valve position displacement if external forces act upon the closing element – a critical safety characteristic for large valves subject to flow-induced torque reversal. The worm wheel is made of spheroidal cast iron as standard, with certain applications requiring alternative materials depending on duty and environment.
End stops use a traveling nut principle in accordance with AWWA C504, providing precise, adjustable limits for the swing angle, which can range from 0° to 190° or be configured for multi-turn operation without end stops entirely. The gearbox can be operated either manually via handwheel directly, or by motor operation using a combined AUMA electric multi-turn actuator, giving plant operators both emergency manual control and automated electric operation from the same gearbox platform.
Engineering Design of the GS Gearbox
The GS gearbox housing is made of cast iron as standard, with AUMA recommending spheroidal cast iron housings where extreme external loads must be considered. All parts within the power drive are subjected to thermal hardening treatment, and the gearbox output drive conforms to ISO standard flange dimensions for compatibility with standard valve mounting. The gearbox is available with or without primary reduction gearing, and features a 360° worm wheel to support the full range of swing angle and multi-turn configurations.
Rated to IP68 protection with high-quality corrosion protection, the GS gearbox operates across an exceptionally wide ambient temperature range of -60°C to +120°C, supporting installations from arctic to extreme desert climates. When combined with an SA multi-turn actuator, the assembly is supplied in enclosure protection IP68-3, and reduction ratios spanning 39:1 to 3,328:1 allow the gearbox to be matched precisely to the actuator size and valve torque requirement.
Key Features
The AUMA GS Part-Turn Gearbox delivers high-torque quarter-turn valve automation beyond standard actuator limits. Key characteristics include:
- Torque capacity up to 675,000 Nm when combined with an AUMA SA multi-turn actuator.
- Reduction ratios from 39:1 to 3,328:1 to match actuator size and valve torque requirement.
- Swing angle from 0° to 190°, or configurable for multi-turn operation without end stops.
- Self-locking worm gear design prevents valve position displacement from external forces.
- IP68 protection with high-quality corrosion protection across -60°C to +120°C ambient range.
- End stops with traveling nut principle per AWWA C504; ISO-standard output drive.
- Manual handwheel operation or motor operation via combined AUMA multi-turn actuator.
Industrial Applications
The GS gearbox is deployed wherever large butterfly valves, ball valves, or dampers require torque beyond the reach of standard part-turn actuators, including major pipeline isolation valves, power plant flue gas dampers, water infrastructure projects with large-diameter valves, and industrial process lines with high-torque quarter-turn valve requirements. Its self-locking characteristic makes it particularly suited to applications where flow-induced torque reversal must not be allowed to displace valve position.
Seven Star LLC supports power generation engineering teams, water authorities, and heavy industrial plant operators across Oman, Muscat, Sohar, and the broader GCC region with sourcing of AUMA GS part-turn gearboxes, helping projects automate their largest, most demanding quarter-turn valves.
Technical Specifications
The table below summarizes the core specifications of the AUMA GS Part-Turn Gearbox as supplied by Seven Star LLC.
| Parameter | Specification |
|---|---|
| Model | AUMA GS 50.3 – GS 630.3 |
| Type | Right-angle worm gear part-turn gearbox |
| Torque Capacity | Up to 675,000 Nm (combined with SA actuator) |
| Reduction Ratios | 39:1 to 3,328:1 |
| Swing Angle | 0° to 190°, or multi-turn without end stop |
| Protection Class | IP68 (IP68-3 combined with SA actuator) |
| Ambient Temperature | -60°C to +120°C |
| Duty Rating | S2-15 min (open-close) and positioning; S4-25% modulating (bronze only) |
| Output Drive | ISO standard flange |
Sizing, Valve Attachment and Corrosion Protection
The AUMA GS Part-Turn Gearbox range is graduated so that each frame size covers a defined torque band, allowing an engineer to select the smallest gearbox that still carries the valve’s break and seating torque with margin. Within the GS .3 series the GS 50.3 covers 250 to 500 Nm, the GS 63.3 500 to 1,000 Nm, the GS 80.3 1,000 to 2,000 Nm, the GS 100.3 2,000 to 4,000 Nm, the GS 125.3 4,000 to 8,000 Nm, the GS 160.3 8,000 to 14,000 Nm, the GS 200.3 16,000 to 28,000 Nm and the GS 250.3 32,000 to 56,000 Nm, with the larger frames continuing into the hundreds of thousands of newton metres for the biggest butterfly and damper duties.
The gearbox is bolted to the valve through a mounting flange standardised to EN ISO 5211, and the output coupling can be supplied unbored, pilot-bored or finish-bored with keyway, square or two-flat form to suit the valve shaft. On the input side, mounting for an AUMA SA multi-turn actuator follows EN ISO 5210 or, as an alternative, DIN 3210. Where manual input torque would otherwise be excessive, GZ or VZ primary reduction gearing with ratios from 4:1 to 64:1 can be fitted ahead of the worm stage. Three corrosion protection classes are offered – KN as standard for outdoor installation and slightly aggressive atmospheres, KS for occasionally or permanently aggressive atmospheres, and KX for aggressive atmospheres combining high humidity with high pollutant concentration – which matters directly for coastal and refinery installations along the Omani seaboard. The standard finish is silver-grey, similar to RAL 7037.
Operation, Indication and Service Life
A mechanical pointer in the cover shows valve position and running indication without any power supply, and where a remote position signal is required, electronic position transmitters such as the WSG 90.1 or WGD 90.1 provide a 4 to 20 mA feedback signal to the control room. Enclosure protection is verified to EN 60529. Expected service life depends directly on loading: AUMA rates the gearbox for roughly 4,000 to 15,000 OPEN-CLOSE-OPEN cycles at 100% of rated torque, falling to about 1,200 to 5,000 cycles at 140% load and 750 to 1,000 cycles where the gearbox is worked at 175 to 200% of rating. Selecting a AUMA GS part-turn gearbox one frame larger than the bare torque calculation therefore buys a substantial increase in mechanical life on high-cycle isolation and damper service.
Request a Quote for AUMA GS Part-Turn (Quarter-Turn) Gear Boxes
Seven Star LLC supplies the AUMA GS part-turn gearbox with full manufacturer documentation and regional technical support. Contact our instrumentation and valve automation division for a formal RFQ, to confirm the correct gearbox size and reduction ratio for your large-torque valve application, or to obtain the complete technical datasheet. Seven Star LLC ensures every unit shipped across Oman and the GCC is genuine, correctly configured, and backed by local engineering support.
To combine a multi-turn actuator with this gearbox, see the AUMA SA+GS actuator and part-turn gearbox combination.
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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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