Schneider Electric 8740003000 LF24 Damper Actuator 4Nm

8740003000: LF24 electric damper actuator, 4 N.m

The 8740003000 is a Schneider Electric rotary electric actuator for air dampers, rated 4 N.m, with 2-position (on/off) control, spring return and a supply of 24 V AC/DC. The datasheet lists a 1 m lead and an IP54 rating, and the actuator model is LF24. Seven Star LLC supplies it as an independent supplier in Oman and the GCC for HVAC contractors, BMS integrators and facility teams.

The LF24 is the only spring-return unit in this group. When power is lost, its spring drives the damper to the safe position in about 20 seconds, which is the feature to look for on fire, smoke and freeze-protection duties. The datasheet title and the actuator model are the only available decoding: LF is the spring-return series, a reading taken from the product titles, not from an ordering table.

Selection checklist for the 8740003000

• Torque: damper requirement from the damper maker must be at or below 4 N.m with margin.
• Control signal: 2-position (on/off); match the controller output.
• Failure position: spring return.
• Supply: 24 V AC/DC, with a transformer rated for at least 7 VA per actuator.
• Shaft: confirm damper shaft size against the actuator clamp before ordering.
• Environment: IP54 and -30 to 50 °C operation; indoor or sheltered locations only.

Technical specifications of the 8740003000

Return behaviour and failure position of the 8740003000

On loss of supply the internal spring returns the damper in 20 seconds, so an outside-air damper closes on a freeze trip and a smoke damper can be driven to its safe position. That behaviour is the reason to choose this actuator over the MD series. A hand wrench slot (5/32 inch) allows manual override during commissioning or fault finding.

In Gulf buildings a spring-return actuator also protects coil and ductwork when the building supply trips during heavy summer load. The position indicator is a stroke indicator on the bracket, which helps a technician see the state without opening the ceiling void.

Typical uses of the 8740003000 in Oman and the GCC

Damper actuators of this class operate fresh-air, return-air and mixing dampers in air-handling units, fan-coil plenums and ventilation ducts in commercial buildings, hospitals, hotels and plant buildings. Spring return makes it suitable for fire and freeze duty. Operating air temperatures up to 50 °C and humidity up to 95 % non-condensing cover typical plant-room conditions in the region.

For sites with fine desert dust, keep the actuator out of direct airstreams where possible and inspect the shaft coupling at each filter change. High summer temperatures inside rooftop air-handling casings can approach the 50 °C operating limit, so check the real casing temperature before committing.

Comparison of the 8740003000 with sibling actuators

The two 5 N.m two-position references differ in that one lists two SPDT switches and a 24 V AC supply. Always compare supply type and signal before treating two similar-looking actuators as interchangeable.

How the 8740003000 drives a damper

The actuator mounts directly on the damper shaft and turns it through a stroke of 95 degrees, which can be trimmed between 37 and 100 degrees. Stroke running time is 150 s with a no-load time of 40 seconds, so the damper takes a couple of minutes to travel from end to end, which is slow enough to avoid air-pressure shocks in ductwork.

Control is on/off: power applied drives the damper to one position and removing or reversing it drives the other. Power consumption is 5 W while moving and 2.5 W when holding, with a transformer rating of 7 VA. This is a Class III insulated device, meant for extra-low-voltage supplies only.

Installation and commissioning of the 8740003000

Fit the actuator on the damper shaft, set the end stop or mechanical limits, and wire the 1 m lead to the control panel through a suitably rated 24 V supply. Never connect mains voltage to this device. Dress the cable so that condensation cannot run along it into the housing.

Cycle the damper by hand or by control, watch the full travel for binding, and record the running time. Replace an actuator that struggles to reach end position instead of raising its supply. Keep spare units of this unit for critical dampers, because a seized damper often shows up only during a hot-weather commissioning test.

When several actuators share one 24 V transformer, add up the VA ratings, not the watts, and leave headroom for simultaneous starting. Label each lead with its damper tag at the panel end so that a technician can trace a fault from the controller to the shaft without opening ductwork. A wiring check before first power saves the most time: confirm polarity or phase assignment against the controller documentation, because a reversed connection will simply drive the damper the wrong way.

Information to send with an RFQ for the 8740003000

• Exact reference 8740003000 and quantity.
• Damper torque requirement and shaft size.
• Control signal and supply voltage of the BMS.
• Fail-safe requirement.
• Delivery location and project schedule.

Documents and quotation

The manufacturer datasheet for the 8740003000 is attached on this page and carries the specification summarised above. Check the revision date against your project.

Send us the reference 8740003000, quantity and delivery location and Seven Star LLC will reply to your request. We are an independent supplier based in Muscat.