AUMA SAR 10.2 Modulating Multi-Turn Actuator

Overview

AUMA SAR 10.2 is an AUMA NORM multi-turn actuator for modulating duty (class C, ISO 22153) with a tripping-torque window of 60 to 120 Nm and 10 output speeds from 4 to 90 rpm. SAR 10.2 offers 60 to 120 Nm of tripping torque and up to 60 Nm of modulating torque at S4-25 percent. It is the first SAR size with a dedicated F10 interface and a 40 mm stem bore, supplied with a 200 mm handwheel.

The SAR 10.2 is supplied by Seven Star LLC, a trusted AUMA supplier for Oman and the GCC, with correct documentation and a regional contact for commissioning.

Operating Principle

The SAR 10.2 is positioned by short motor pulses from an AM or AC positioner and keeps its position by self-locking. Modulating torque is 60 Nm (S4 – 25 percent) at 4 to 45 rpm and 50 Nm at 63 to 90 rpm, and a pulse of 50 ms is the minimum.

Engineering Design of the AUMA SAR 10.2

With 1,500 starts per hour up to 45 rpm and 1,200 at 63 and 90 rpm, a minimum pulse duration of 50 ms and a reversal pulse of 60 to 260 ms, the SAR 10.2 comfortably handles loop-controlled positioning. Where a valve is expected to work continuously at the edge of its modulating torque, the S4-50 percent figures should be used instead of the S4-25 percent ones.

Key Features

What stands out on the SAR 10.2:

• Modulating multi-turn actuator for mid-sized control valves.
• 60 Nm is the lowest and 120 Nm the highest tripping setting, a 2.0 to 1 range.
• 90 Nm is the S4 – 50 percent limit, about 75 percent of the largest tripping setting.
• The torque-to-weight ratio at full setting is 4.8 to 5.5 Nm/kg.
• An illustrative stroke of 20 turns takes about 54.5 seconds at 22 rpm.
• Neighbouring frames are the SAR 07.6 and the SAR 14.2.
• Dimension and electrical data are published by AUMA in separate documents.

Selecting the AUMA SAR 10.2

In the SAR series the AUMA SAR 10.2 is where positioning duty meets mid-sized control valves. The modulating torque is 60 Nm (S4-25 percent) and 45 Nm (S4-50 percent) up to 45 rpm, and 50 Nm and 35 Nm at 63 and 90 rpm. It is slightly heavier than the 07 sizes at 22 to 25 kg. The minimum tripping torque of 60 Nm should be compared with the valve: control valves with a small seat and light packing may need only 25 Nm, in which case a SAR 07.6 is better matched.

Typical partners are globe control valves with larger trim, modulating gate valves, cooling-water and condensate control valves, flow-control valves on pump discharge lines and rising-stem valves in water-treatment filtration plants.

A positioner does not only drive the valve; it also learns how the valve reacts. On the AUMA SAR 10.2 the 60 to 120 Nm tripping window leaves ample margin for torque switching, but the modulating torque of 60 Nm at S4-25 percent is the figure that counts for controller tuning. If the valve plug sticks at low lift, small set-point changes produce no movement until the pulse is long enough, and then the plug jumps. Choosing a lower output speed gives finer steps, which usually improves control quality more than any adjustment of controller gain. Once installed, run a full stroke in both directions under control to record the position transmitter calibration and compare the torque trace with the commissioning values, which gives a baseline for later condition monitoring and for diagnosing a sticking valve.

Sizing example for the AUMA SAR 10.2

Consider an illustrative control valve with a running torque of 48 Nm and a seat torque of 95 Nm. The running torque is below the 60 Nm modulating limit at S4-25 percent (up to 45 rpm), and the seat torque falls within the 60 to 120 Nm window of the AUMA SAR 10.2. At 90 rpm the modulating limit is 50 Nm, still enough, but the S4-50 percent figure there is only 35 Nm, so for heavier duty cycles a slower speed is better. A 20-turn stroke at 16 rpm takes 75 seconds. These numbers are an illustrative calculation and not AUMA data.

Installation and Mounting of the AUMA SAR 10.2

At 22 to 25 kg the AUMA SAR 10.2 is a one- or two-person lift. The F10 flange is shared with the SA 10.2 and SAR 07.6, so valve brackets are compatible, but the 200 mm handwheel is bigger than on the 07 sizes. Position the actuator so that the plug/socket connector and the controls are accessible, and specify the stem protection tube if the stem protrudes through the actuator.

Industrial Applications

In water-treatment works at Barka, Sohar and Salalah the AUMA SAR 10.2 can control filter-backwash and clarifier outlet valves, while in district-cooling plants it throttles chilled-water bypass and header balancing valves. Power and cogeneration plants use it on desuperheater and condensate return control.

In Oman and the GCC, Seven Star LLC also supplies the AUMA SAR 14.1 multi-turn actuator, the AUMA MATIC AM/AC integral actuator controls and the AUMA SAREx explosion-proof modulating actuator.

Neighbouring sizes and counterparts: AUMA SAR 07.6 modulating actuator, AUMA SAR 14.2 modulating actuator and AUMA SA 10.2 multi-turn actuator.

Technical Specifications

Data of the AUMA SAR 10.2 from the AUMA technical data sheet for 3-phase AC motors.

Setpoint guide for the SAR 10.2 (illustrative calculation, not AUMA data)

Stroking time for 20 turns at the SAR 10.2 (illustrative calculation, not AUMA data)

Request a Quote for AUMA SAR 10.2

Planning a regulating loop with the AUMA SAR 10.2? Send Seven Star LLC your quantities, supply voltage and controls, then open the AUMA datasheet from this page.