AUMA GST Spur Gearboxes (Multi-Turn)

Overview: Repositioning the Drive Axis for Restricted Installations

The AUMA GST Spur Gearbox is a right-angle multi-turn gearbox used when an AUMA SA multi-turn actuator’s drive shaft needs to be positioned at a certain angle to the valve’s output drive shaft, whether due to space constraints, access requirements, or valve orientation. Combining an SA actuator with a GST gearbox not only repositions the drive axis but also multiplies the output torque significantly beyond what the actuator alone could deliver, extending AUMA’s multi-turn actuator range up to combined torques of 16,000 Nm.

As an authorized supplier of AUMA valve gearboxes, Seven Star LLC sources and supplies the GST spur gearbox to power plants, water treatment facilities, and heavy industrial process plants across Oman and the wider GCC. Because SA/GST combinations solve both torque-extension and installation-geometry problems simultaneously, Seven Star LLC helps engineering teams specify the correct gearbox reduction ratio and mounting configuration for their project.

Working Principle: Torque Multiplication Through Gear Reduction

The GST gearbox uses a spur gear train to transmit rotational drive from the multi-turn actuator to the valve stem, with the gearbox’s reduction ratio – available from 1:1 up to 22:1 – determining how much the actuator’s input torque is multiplied at the output while proportionally reducing output speed. This is the same fundamental gear-reduction principle used across mechanical power transmission, applied here specifically to valve automation duty where reliability, corrosion resistance, and precise manual operation matter as much as raw torque multiplication.

The GST gearbox shifts the multi-turn actuator physically out of the valve stem axis, which is particularly valuable where restricted access around the valve would otherwise make actuator mounting or handwheel operation difficult; by offsetting the actuator, operators retain free access to the actuator handwheel and controls even in tight installation environments. GST gearboxes with a 1:1 reduction ratio are also available for smaller torques up to 120 Nm, addressing special installation applications where axis offset is needed but torque multiplication is not.

Engineering Design of the GST Gearbox

The GST gearbox is built with a stainless steel input shaft and top-quality corrosion protection using AUMA’s powder coating system, rated IP68 for reliable operation in wet, humid, or submerged installation environments. The gearbox is suitable for both manual and electrical operation, supporting valve commissioning and emergency operation independent of actuator power.

Configuration options include a square adapter for the input shaft, a stem nut version for use as a screw jack, a stem protection tube, position and end-position signaling during manual operation, a second shaft end with or without protective cap, ATEX approval for hazardous-area installations, and high- or low-temperature versions for extreme ambient conditions. This breadth of options allows the GST platform to be adapted to a wide range of project-specific mounting and signaling requirements.

Key Features

The AUMA GST Spur Gearbox extends multi-turn actuator capability for demanding torque and installation requirements. Key characteristics include:

• Torque capacity up to 16,000 Nm when combined with an AUMA SA multi-turn actuator.
• Reduction ratios from 1:1 to 22:1 to match torque multiplication and speed requirements.
• Right-angle output shifts the actuator out of the valve stem axis for restricted-access installations.
• Stainless steel input shaft with IP68 protection and AUMA powder coating corrosion protection.
• Suitable for both manual and electrical operation.
• Optional ATEX approval, stem protection tube, position signaling, and high/low temperature versions.

Industrial Applications

The GST gearbox is deployed wherever gate valves or globe valves require multi-turn actuation with either higher torque than a standalone actuator provides or a repositioned drive axis due to installation constraints, including power plants (conventional, hydroelectric, geothermal, and solar thermal), water and sewage treatment plants, and general heavy process industry. Its combination with AUMA SA actuators makes it a standard solution for extending torque range across AUMA’s broader valve automation portfolio.

Seven Star LLC supports power generation engineering teams, water authorities, and industrial plant maintenance departments across Oman, Muscat, Sohar, and the broader GCC region with sourcing of AUMA GST spur gearboxes, helping projects solve both torque and installation-geometry requirements in a single proven combination.

Technical Specifications

The table below summarizes the core specifications of the AUMA GST Spur Gearbox as supplied by Seven Star LLC.

Call To Action

Seven Star LLC supplies the AUMA GST spur gearbox with full manufacturer documentation and regional technical support. Contact our instrumentation and valve automation division for a formal RFQ, to confirm the correct reduction ratio and mounting configuration for your gate or globe valve, 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.