SAMSON Type 3374 Electric Linear Actuator
Overview
The SAMSON Type 3374 is an electric linear actuator for valves used in heating, ventilation and air-conditioning systems and in plant engineering. It is designed to be combined with SAMSON Series V2001 and Series 240 valves as well as Type 3260 and Type 3214 valves, giving a complete electrically actuated control valve without the need for compressed air. The SAMSON Type 3374 is offered with a three-step control signal or with an integrated digital positioner, with or without fail-safe action, and in two mechanical styles: form B with an integrated yoke and form A with an M30 x 1.5 ring nut. SAMSON describes the design as maintenance free, with the motor switched off by torque switches.
Seven Star LLC supplies the SAMSON Type 3374 actuator and SAMSON valve combinations to HVAC contractors, building services engineers, district cooling operators and industrial plant teams in Muscat, the Sultanate of Oman and the GCC. We provide engineering support in Muscat for selecting thrust, travel, signal type and fail-safe action for each valve.
Operating Principle
The SAMSON Type 3374 consists of a reversible motor and a maintenance-free planetary gear with ball screw drive that converts rotation into linear stem movement. In the three-step version a synchronous motor is used: the controller energises one input to extend the stem and another to retract it, and the stem stays in position when neither is active. In the positioner version a stepper motor is used, and the built-in electronics compare the 0/4 to 20 mA or 0/2 to 10 V input with the actual travel and move the stem until they match. The motor stops on torque switches in the end positions or in the event of overload, protecting both the actuator and the valve seat.
Fail-safe versions of the SAMSON Type 3374 contain a spring assembly and an electromagnet. While the electromagnet is energised the spring is held; when supply voltage is lost, the spring drives the stem to the fail-safe position at 1.25 mm/s, completing the rated travel in 12 or 24 s. Depending on the version the stem extends or retracts on power failure, and the direction cannot be reversed afterwards. The actuator stem extends fail-safe action has been tested by TUV according to DIN EN 14597 in combination with various SAMSON valves, which is relevant for temperature limiting functions in heating systems.
Engineering Design of the SAMSON Type 3374
The SAMSON Type 3374 housing and cover are made of glass-fibre reinforced PPO plastic, rated IP65 to EN 60529 with the cable glands mounted (suspended mounting is not permitted), protection class II and three M20 x 1.5 polyamide cable glands for 6 to 12 mm cables. Permissible ambient temperature is 5 to 60 °C with humidity of 5 to 95% without condensation. Rated travel is 15 or 30 mm depending on the version, and thrust ranges from 0.5 kN up to 5 kN, with safety spring thrusts between 0.5 and 3 kN. A mechanical override is available with a hex wrench, and weights range from about 3.2 to 6.2 kg.
The positioner version is configured with a rotary pushbutton on the actuator or with SAMSON TROVIS-VIEW software, and a special version with three keys on the cover allows operation without removing the housing. It provides a 0/4 to 20 mA or 0/2 to 10 V position feedback output, a binary output and binary inputs, a Pt1000 input with a fixed set point PID function, and an optional RS-485 module for Modbus RTU. Options include two mechanical limit contacts rated 240 V AC and 1 A, electronic limit contacts via relay, and on three-step versions two 0 to 1000 ohm resistance transmitters for position feedback.
Key Features
Key features of the SAMSON Type 3374 from SAMSON data sheet T 8331 are:
- Electric linear actuator for SAMSON Series V2001, Series 240, Type 3260 and Type 3214 valves.
- Three-step version with synchronous motor or positioner version with stepper motor.
- Thrust up to 5 kN and rated travel of 15 or 30 mm.
- Optional fail-safe action with spring, stem extends version tested to DIN EN 14597.
- Planetary gear with ball screw drive and torque switch-off, no maintenance required.
- Positioner inputs 0/4 to 20 mA or 0/2 to 10 V with position feedback output.
- Optional limit contacts, resistance transmitters and Modbus RTU communication.
- IP65 glass-fibre reinforced plastic housing with protection class II.
Industrial Applications
The SAMSON Type 3374 is typically used on two-way and three-way globe valves controlling hot water, chilled water and steam in heating, ventilation and air-conditioning systems, district heating and cooling substations, heat exchangers, air handling units and domestic hot water preparation. In industrial plants it serves utility circuits, temperature control of process water and thermal oil, and small steam pressure loops where compressed air is not available or not desired. The built-in PID function with a Pt1000 input allows the SAMSON Type 3374 to work as a simple stand-alone temperature controller, and Modbus RTU suits connection to building management systems.
In Oman and the GCC the SAMSON Type 3374 is well suited to district cooling energy transfer stations, central chilled water plants in hotels, hospitals, malls and office towers in Muscat, airport and campus utilities, and industrial cooling water circuits. Installation should respect the ambient limit of 60 °C, so plant rooms and shaded or ventilated locations are preferred in hot climates. Seven Star LLC supplies the SAMSON Type 3374 with matching SAMSON valves and V2001 mounting kits, and supports the choice between three-step and positioner control.
Technical Specifications
The SAMSON Type 3374 data below are taken from SAMSON data sheet T 8331 EN (edition May 2025).
| Parameter | Specification |
|---|---|
| Model | SAMSON Type 3374 electric actuator, versions -10, -11, -15, -17 (no fail-safe), -21, -25, -26, -27 (stem extends), -31, -35, -36 (stem retracts) |
| Style | Form B with integrated yoke; form A with M30 x 1.5 ring nut |
| Rated travel | 15 or 30 mm depending on version |
| Thrust | 0.5 to 5 kN depending on version and direction |
| Safety spring thrust | 0.5 to 3 kN (fail-safe versions) |
| Stroking speed (positioner) | 0.125 to 1 mm/s depending on motor and speed setting; 1.25 mm/s on fail-safe action |
| Supply, three-step version | 230 V or 24 V, +10/−15%, 50 Hz |
| Supply, positioner version | 24 V AC/DC ±15% or 100 to 240 V AC, 50 to 60 Hz |
| Positioner input / output | 0/4 to 20 mA or 0/2 to 10 V; Pt1000 input; 0/4 to 20 mA or 0/2 to 10 V output |
| Communication | Optional RS-485 module for Modbus RTU |
| Motor switch-off / duty | Torque switches; S1 100% to EN 60034-1 |
| Ambient temperature | 5 to 60 °C; storage −25 to +70 °C |
| Degree of protection | IP65 with cable glands mounted; protection class II |
| Housing material | Glass-fibre reinforced PPO plastic |
| Weight | Approx. 3.2 to 6.2 kg depending on version |
How to Order
For a quotation on the SAMSON Type 3374, send Seven Star LLC the valve type and size, required thrust and travel, control signal (three-step or analog), supply voltage, fail-safe action and options such as limit contacts or Modbus. The SAMSON data sheet T 8331 can be downloaded from this page. Seven Star LLC supplies SAMSON actuators and valves in Oman and the GCC with engineering support in Muscat. See also the SAMSON Type 3271 Pneumatic Diaphragm Actuator, the SAMSON Type 3277 Pneumatic Actuator for Integral Positioner Attachment and the SAMSON Type 3241 Globe Control Valve.
- Datasheet SAMSON Type 3374 Electric Actuator Data Sheet T 8331 EN (manufacturer) Download
Samson valve, actuator and positioner types
Samson builds a control valve from modules. The Type 3241 globe valve is the general-service body of Series 240, and the Type 3251 is the Series 250 body for higher pressure ratings. Either one is combined with a Type 3271 pneumatic diaphragm actuator or a Type 3277, whose yoke allows the positioner to be attached directly with a concealed travel linkage. The positioners listed are the Type 3725 and the Type 3730 family: the 3730-1 as the basic electropneumatic version, sold in its current generation as TROVIS 3730-1, and the 3730-3 with HART communication and valve diagnostics. Samson also makes PROFIBUS PA and FOUNDATION fieldbus variants in the same family, plus self-operated pressure and temperature regulators.Where Samson valves are used
Samson control valves throttle steam, gas and liquids in chemical and petrochemical units, refineries, gas processing, power stations, water and desalination plants, and food production. Many reach site as part of a skid or package, so the plant instrument team often meets them first when a positioner or actuator needs replacing. We supply these items to end users and contractors throughout the GCC.Ordering Samson parts: what we need
Every Samson device has a nameplate with the type, a configuration ID (Var-ID) and a serial number. A photo of that plate is the surest route to an exact match. Without it, please send:- Valve: type, DN or NPS, pressure rating, body and trim material, Kvs or Cv, plug and seat style, packing and bonnet type
- Actuator: type, effective area in cm², bench range, fail action and travel
- Positioner: full type code including Ex protection, communication and options such as limit switches or position transmitter
Browse Samson products by category: Control Valves, Valve Positioner, Valve Actuator.
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