This spring return damper actuator combines 24 V two-position control with automatic return after power loss. It is intended for ventilation dampers that must move to a defined standby or protective position when the electrical supply disappears. Two configurations provide 4 Nm or 5 Nm torque with 3-second or 7-second travel.
Spring Return Damper actuator Overview
What the Actuator Controls
The actuator drives a compatible ventilation damper between two end positions. With power and the appropriate command present, it moves the shaft to the operating position. When power is removed, the return mechanism drives the shaft toward the configured opposite end. Whether that movement opens or closes the damper depends on mounting orientation and blade geometry.
Where Power-Loss Return Adds Value
This architecture is useful when a ventilation branch, equipment connection or room-air sequence needs a predictable damper position after loss of 24 V power. Typical duties include laboratory supply and exhaust fallback, equipment isolation, ventilation standby and pressure-control recovery sequences. The required position must be defined in the project sequence rather than inferred from the term spring return.
Actuator-Only Supply Boundary
The product is a damper actuator, not a complete motorized damper or airflow-control system. Damper body, blade, shaft, seals, linkage, airflow sensing, controller programming and system acceptance remain separate unless they are expressly included in the quotation. A returned actuator position does not by itself prove airflow, leakage performance, smoke containment or process isolation.
Product Selection Summary
Choose This Actuator When
Select this spring return damper actuator when the control task is two-position, AC/DC 24 V power is available, and the damper must automatically move to a defined end position after power loss. The installed mechanism must remain within the selected 4 Nm or 5 Nm torque capacity after the required engineering margin is applied.
Choose the 3-second, 4 Nm configuration where rapid travel and a low mechanical load are the primary requirements. Choose the 7-second, 5 Nm configuration where the damper needs greater torque. Runtime does not replace torque verification: seal friction, differential pressure, blade condition and breakaway load can make a small damper difficult to move.
Evaluate Another Actuator Type When
Use an on/off direct-coupled damper actuator when powered open/close movement is required without automatic power-loss return. Evaluate a modulating damper actuator when the system must position the blade between its end stops. A certified fire or smoke damper requires an actuator and damper assembly carrying the applicable project approval.
Information Required for Selection
Provide the damper type, calculated or measured torque, shaft dimensions, required powered position, required power-loss position, allowable drive and return times, AC or DC 24 V supply, command logic, feedback requirement, mounting orientation and ambient conditions. Include the damper drawing and control sequence where available.
Key Specifications and Configuration Selection
Dimensions and Installation Envelope
The dimensional drawing applies to both available spring-return configurations. Confirm the 129.6 x 69.2 x 54.5 mm enclosure, shaft position, cable exit and service access against the damper arrangement before selecting the torque and travel-time option.
| Configuration | Torque | Travel Time | Supply | Control | Power-Loss Function |
|---|---|---|---|---|---|
| 3S4N | 4 Nm | 3 s | AC 24 V, 50/60 Hz or DC 24 V +/-10% | Digital open/close | Automatic return to the configured end position |
| 7S5N | 5 Nm | 7 s | AC 24 V, 50/60 Hz or DC 24 V +/-10% | Digital open/close | Automatic return to the configured end position |
Shared Mechanical and Environmental Data
| Field | Available Value | Selection Check |
|---|---|---|
| Shaft interface | 12-15 mm round or 10 x 10 mm square; minimum 40 mm engagement | Measure the actual shaft before ordering |
| Rotation | Maximum 90 degrees, switch-adjustable | Match the travel limit to the installed blade |
| Direction | Selectable by direction switch | Document the powered and de-energized blade positions |
| Position indication | Local scale | Verify indicated and actual blade positions during commissioning |
| Manual operation | Manual gear release | Maintain safe access to the release control |
| Protection | IP53 | Confirm that the location does not require a higher enclosure rating |
| Connection | Approximately 900 mm, three-core 0.68 mm2 cable | Coordinate conductor identification and junction location |
| Envelope and weight | 129.6 x 69.2 x 54.5 mm; approximately 612 g | Allow shaft, cable and removal clearance |
IP53 and the CE reference do not establish fire/smoke certification, explosion protection, outdoor weatherproofing or washdown suitability. Match any regulated or severe environment to the required approval before specifying the actuator.
Direct-Coupled Mounting and Mechanical Fit
Shaft and Torque Compatibility
The clamp accepts a 12-15 mm round shaft or a 10 x 10 mm square shaft with at least 40 mm engagement. Confirm shaft profile, usable insertion length, clamp range and anti-rotation restraint. Select torque from the damper’s breakaway load, seal friction, differential pressure and contamination allowance rather than duct diameter alone.
Mounting Orientation and Return Direction
Establish the blade’s open and closed positions before fitting the actuator. The same rotational return direction can represent open on one damper and closed on another. Record the relationship between actuator scale, shaft rotation and blade position so the de-energized state is unambiguous to installers and controls technicians.
Service Clearance
Coordinate the 129.6 x 69.2 x 54.5 mm body with the shaft centerline, cable route, manual-release access and removal path. Leave enough room to operate the direction and release controls without removing adjacent ductwork. The anti-rotation restraint must prevent body movement without placing side load on the shaft or damper bearings.
Power-Loss Control and Electrical Coordination
Define the Normal and De-Energized Positions
The actuator uses powered control to move the damper to its operating end position. Removing the supply releases the return mechanism and moves the shaft to the configured opposite end. State the resulting blade position as open or closed in the sequence of operation; clockwise or counterclockwise direction alone is not sufficient.
Separate Drive Time, Return Time and Alarm Delay
The 3-second and 7-second values identify the two available configurations, but a time-critical project should state allowable powered travel and allowable power-loss return time separately. The controller’s fault delay should also allow for actual damper travel so a normal transition is not reported as a failure.
24 V Command and Feedback
The actuator accepts AC 24 V at 50/60 Hz or DC 24 V within the stated tolerance. Confirm conductor functions against the wiring document supplied with the selected configuration before energization. Where passive position feedback is required, define the receiving input and contact logic in the panel schedule.
Feedback reports actuator state; it does not independently prove blade position if the shaft clamp slips. Commissioning must compare the command, local scale, shaft movement, actual blade position and remote indication.
Transformer and Circuit Sizing
Size the 24 V transformer, switching contacts and conductors for the selected actuator and the number of units that can move simultaneously. Include starting demand and cable voltage drop. Confirm model-specific running and holding consumption in the order documentation before releasing the control panel.
Limits of the Power-Loss Function
Automatic return defines actuator behavior after loss of supply. It does not establish damper leakage, smoke containment, fire endurance, measured airflow or process isolation. Those outcomes depend on the complete damper assembly, installation and any required certification.
Applications and Project Fit
Laboratory and Equipment Ventilation
This spring return actuator can serve laboratory supply or exhaust dampers, equipment ventilation branches and pressure-control fallback sequences where loss of 24 V power must produce a planned blade position. The 3-second option prioritizes rapid movement for a low-torque mechanism, while the 7-second option provides 5 Nm for a higher mechanical load.
Standby and Isolation Sequences
The actuator can support equipment enable/disable, ventilation standby and branch-isolation sequences when the damper’s required powered and de-energized positions are clearly documented. System behavior should be tested with the fan, controller, alarms and interlocks rather than evaluating the actuator alone.
Applications That Require a Different Product
This family does not provide proportional blade positioning or a closed-loop airflow controller. It is not documented as a fire/smoke actuator, explosion-proof device, outdoor weatherproof actuator or chemical-resistant process component. Use an appropriately rated product where the project requires those functions.
Environmental Fit
The IP53 rating does not cover driving rain, washdown, persistent condensation or corrosive-gas exposure. Confirm ambient temperature, humidity, water exposure and chemical atmosphere. Evaluate the corrosion-resistant on/off damper actuator when environmental exposure is the main selection driver, while separately determining whether automatic power-loss return is still required.
How to Select and Specify a Spring Return Damper actuator
1. Define the Failure Position
State the required blade position with power present and after power loss. Translate the selected return direction into an actual open or closed position for the installed damper.
2. Confirm Torque and Shaft Fit
Use measured or calculated breakaway torque with the project margin, then choose 4 Nm or 5 Nm. Verify the 12-15 mm round or 10 x 10 mm square shaft and at least 40 mm engagement.
3. Set Timing Requirements
Specify maximum powered travel time, maximum return time and controller alarm delay separately. Select the 3-second or 7-second configuration only after both torque and sequence timing are acceptable.
4. Complete the Electrical Schedule
Confirm AC or DC 24 V, conductor functions, transformer capacity, command logic and required feedback. Identify how many actuators may operate at the same time and the longest cable run.
5. Review the Installation Environment
Check service clearance, mounting orientation, condensation, water exposure, chemical atmosphere and the required enclosure rating. IP53 should not be extended to duties it does not cover.
Quotation Input Checklist
For each damper tag, provide the application, normal and power-loss positions, torque calculation, drive and return times, shaft dimensions, orientation, 24 V supply, command and feedback logic, ambient conditions, quantity and destination. The quotation should identify the selected configuration, supplied electrical scope, dimensions and any project conditions that still require confirmation.
Installation and Commissioning
Mechanical Installation
Verify free blade movement before mounting. Align the shaft and clamp without side load, provide at least 40 mm engagement and secure the anti-rotation restraint. Set maximum travel to the required blade stroke instead of forcing the actuator against an obstruction.
Use the manual release only under a controlled procedure. Stored return energy can move the shaft when the mechanism is disengaged or power is removed, so hands and tools must remain clear of the travel path.
Electrical Installation
Confirm AC or DC 24 V, conductor functions, polarity where applicable and the intended powered direction. Use the selected configuration’s electrical data to size the transformer, relay contacts and cable. Check voltage at the actuator when multiple units move simultaneously.
Functional Commissioning Sequence
- Record the actuator configuration, torque, voltage, damper tag and required power-loss position.
- Verify shaft fit, engagement, clamp security, restraint and free blade travel.
- Apply power and command the operating end position.
- Measure powered travel and compare the local indication with actual blade position.
- Remove power under controlled conditions and verify return direction and return time.
- Check feedback at the receiving panel or BMS where fitted.
- Run the complete equipment interlock, alarm and recovery sequence.
Acceptance Records
Record normal position, power-loss position, measured drive and return times, feedback state, final travel setting and observed blade position. These values provide a baseline for periodic functional testing.
Maintenance and Functional Testing
Periodic Power-Loss Test
Test controlled loss of power at an interval appropriate to the ventilation duty. Observe shaft and blade movement, measure return time, inspect the clamp and confirm the actual final position. Checking the actuator scale alone is not enough.
Routine Inspection
Inspect the enclosure, cable, terminals, shaft clamp, mounting restraint, manual release and travel scale. Investigate moisture, corrosion, contamination, abnormal noise or increased resistance. A binding damper can exceed available torque even when the actuator remains electrically functional.
Troubleshooting Guide
| Symptom | Checks | Corrective Direction |
|---|---|---|
| No powered movement | 24 V supply, command, transformer capacity, voltage drop and blade binding | Restore the correct command and remove mechanical resistance |
| Wrong powered direction | Direction setting, conductor assignment and mounting orientation | Correct the configuration and update the control record |
| Wrong position after power loss | Return direction, damper orientation and shaft coupling | Correct the mechanical relationship and repeat the test |
| Slow or incomplete return | Friction, obstruction, torque margin, shaft slip and return mechanism | Repair the damper or reassess actuator selection |
| Feedback disagrees with blade | Contact logic, shaft slip and switch point | Correct the coupling or feedback setup and verify blade position |
Related Damper actuator Options
Compare the on/off direct-coupled damper actuator for powered open/close duty without automatic return, the two-position damper actuator for higher-torque two-state positioning, and the modulating damper actuator for proportional positioning. Select by control task and installed load rather than product name alone.
Frequently Asked Questions
What happens when power is removed?
The actuator automatically returns to its configured end position. The final blade position depends on mounting orientation and return-direction setup, so it must be documented as open or closed for the installed damper.
Are 3 seconds and 7 seconds the spring-return times?
The source publishes them as family travel times but does not separately label powered and de-energized return timing. Both directions should be confirmed when response time is a contract requirement.
What is the difference between 3S4N and 7S5N?
The 3S4N configuration publishes 4 Nm and 3-second travel. The 7S5N configuration publishes 5 Nm and 7-second travel. Both use 24 V digital control and automatic power-loss return.
Does spring return always mean fail closed?
No. The actuator returns in a configured rotational direction. Whether that direction opens or closes the damper depends on the shaft and blade orientation.
Can this actuator be used on a fire or smoke damper?
No fire/smoke listing is published for this product. Use only an actuator and damper assembly carrying the certification required by the project.
Does the product support proportional airflow control?
No proportional input or airflow-control loop is published. This is a digital end-position actuator with automatic return after loss of power.
What shafts can it fit?
The published interface covers 12-15 mm round shafts or 10 x 10 mm square shafts, with at least 40 mm engagement.
Can it operate outdoors?
The published protection rating is IP53. Outdoor exposure, driving rain, washdown, condensation and chemical atmosphere require a separate enclosure and application review.
How should the 24 V transformer be sized?
Use the approved configuration’s running and holding requirements, number of simultaneously operating actuators, cable voltage drop and control-panel margin. The public power line is not sufficiently mapped to size both configurations from one value.
What must be tested during commissioning?
Test powered direction, actual drive time, loss-of-power return direction and time, shaft security, blade position, local indication, feedback and the complete equipment sequence.
Contact the Xicheng Engineering Team Today
Send the damper drawing, required normal and power-loss positions, torque calculation, allowable drive and return times, shaft dimensions, 24 V supply and control schematic. The engineering team will return a recommended configuration, the technical details that need project confirmation and pricing within 24 hours.
Manufacturing Head Office: No. 34 Zhenxing Road (Shengtaian Heavy Industrial Park B), Loucun, Guangming New Dist, Shenzhen, Guangdong, China
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