Measure the inside of your roller tube before you pick a Sonesse 40. Somfy publishes a 38 mm minimum inner diameter for the 406A2, and that one number decides whether the motor goes into the roller you already own. A 1.5 in or a 2 in interior tube clears it. A slim 1.25 in tube does not.
The Somfy Sonesse 40 RTS 406A2 RH with Fast Connector sits in the middle of the Sonesse 40 RTS range, at 6 Nm and 24 rpm, with a round head and a short Fast Connector pigtail. Somfy catalogs it as reference 1240381.
Tube size settles this motor first
Somfy's 400 Series databook prints the rule as a floor rather than a target: an interior tube diameter of 38 mm or greater must be respected. Installers who skip that measurement fight a motor that binds against the tube wall, and the crown never seats. Pull a caliper across the inside of the tube, not the outside. Wall thickness on a 1.5 in aluminum roller runs close enough to the line that the outside measurement misleads you.
The RH in the model name marks a round head. Round-head motors take round-head brackets and plates. Star-head LT50 hardware will not hold this motor, and the two head families do not interchange, so order the bracket against the head you have in hand.
Shades the 406A2 RH suits
Somfy publishes this reference for interior blinds and shades, and for projection screens. Roller shades carry it most of the time. At 6 Nm the motor handles a wide commercial roller or a heavy triple-weave solar screen, and 24 rpm brings a tall drop down at a pace that reads as deliberate rather than slow.
The 44 dB rating earns this motor rooms where a louder drive announces itself: bedrooms, nurseries, media rooms and boardrooms. Somfy engineers the Sonesse range around noise-absorbing brake, rotor and gearbox parts, and the 400 Series databook holds the 406A2 to the same 44 dBA figure the smaller references carry. A projection screen dropping mid-presentation stays out of the conversation.
Verified Somfy specifications
| Somfy reference | 1240381 |
| Somfy designation | 406A2 Sonesse RTS 6/24 FC0.5M |
| Torque / speed | 6 Nm (53 in-lb) / 24 rpm |
| Power supply | 120 V AC, 60 Hz |
| Current | 1.2 A |
| Power in operation | 120 W |
| Standby power | 0.5 W |
| Control | RTS, built-in receiver, 433.420 MHz |
| Sound level | 44 dB |
| Protection index | IP 44 |
| Head type | Round (RH) |
| Minimum tube inner diameter | 38 mm (1.5 in) |
| Motor length | 21.06 in (535 mm) |
| Limit type | Electronic, 250 turns |
| Cable | Fast Connector pigtail, 0.5 m (1.64 ft) |
| Operating temperature | 32 to 140 F |
| Thermal protection | 4 minutes |
| Approval / warranty | UR, 5 years |
Figures come from Somfy's published data for reference 1240381 and the 400 Series databook.
Crowns, drives and tube hardware that match
A Sonesse 40 reaches the tube through two parts. The crown locates the motor head inside the tube, and the drive transfers rotation to the tube wall. Somfy sells them as matched sets, cut to the tube profile, and an installer orders the set that matches the roller rather than the motor.
The Somfy LS40 Crown and Drive Set (9012224) covers the standard 40 mm round tube. For a 2 in roller, the Somfy LS40 2" Crown and Drive Set (9016352) steps the motor out to that profile. Octagonal tubes take the Somfy LS40 Octagonal Rubberized Crown and Drive Set (9016655), where the rubberized face damps the chatter an aluminum-on-aluminum fit can produce under a heavy fabric.
Somfy's 400 Series crown and drive tables run by tube profile and wall thickness. A 40 x 1.0 mm round tube, a 40 x 1.5 mm round tube and a 40 x 0.8 mm octagonal tube each carry their own crown and drive part pair, so check the wall thickness stamped on the roller before you order.
Fast Connector power and wiring
The FC in Somfy's designation marks the Fast Connector pigtail, and 0.5M gives its length: half a meter, or 1.64 ft. A short pigtail keeps a headrail clean. An electrician mates it to a Somfy Fast Connector power lead run back to the junction box, so the motor comes out of the tube later without anyone cutting conductors.
Draw stays light for a 120 V motor. Somfy publishes 1.2 A and 120 W during travel, with 0.5 W at rest. Thermal protection trips after 4 minutes of continuous rotation, which covers any window drop and guards the winding through a long limit-setting session. IP 44 and the 32 to 140 F band keep this reference behind glass, on the interior side.
RTS pairing, limits and TaHoma
RTS lives inside the motor head. The 406A2 RH answers any Somfy RTS transmitter on 433.420 MHz once you pair it, with no external receiver and no separate antenna. The Somfy Situo 1 Channel RTS Pure Remote (1870571) runs a single shade and stores a my position for the halfway stop a client asks for most. Crews commissioning a wall of shades move up to a 5-channel Situo or a 16-channel Telis and assign channels room by room.
Limits are electronic, rated across 250 turns of travel. Set the upper and lower stop from the remote using Somfy's RTS pocket guide sequence. Somfy caps continuous rotation at 3 minutes without a stop, so finish both limits before you come off the ladder.
Adding a TaHoma switch brings the shade into app and voice control. Somfy lists TaHoma compatibility for reference 1240381, which puts schedules, scenes and voice commands on this motor with no change to the hardware in the tube.
Frequently asked questions
What tube does the Sonesse 40 RTS 406A2 RH need?
Somfy requires an interior tube diameter of 38 mm (1.5 in) or greater. Standard 1.5 in and 2 in interior roller tubes clear that figure in round and octagonal profiles. Match the crown and drive set to the tube profile and wall thickness, since a 40 x 1.0 mm round tube and a 40 x 0.8 mm octagonal tube take different parts.
How much torque does the 406A2 deliver?
Somfy rates this reference at 6 Nm, or 53 in-lb, at 24 rpm. That places it above the 4 Nm 404S2 at 36 rpm and below the 9 Nm 409R2 at 14 rpm. Torque rises and speed drops across the range, so a heavier fabric trades travel time for lifting capacity.
Does the Fast Connector pigtail include a power cable?
The motor ships with a 0.5 m (1.64 ft) Fast Connector pigtail at the head. A matching Somfy Fast Connector power lead carries 120 V from the junction box to that pigtail and gets ordered on its own. Confirm the connector on the motor you receive against the lead before an electrician makes the run.
Which remote pairs with this motor?
Any Somfy RTS transmitter on 433.420 MHz pairs with the built-in receiver. The Situo 1 Channel RTS Pure handles one shade, and 5-channel Situo and 16-channel Telis remotes cover grouped shades. DecoFlex RTS wireless wall switches give a fixed station at the door, and a TaHoma switch adds phone and voice control.
Buyers who land on this reference have a 40 mm tube, a round-head bracket and a preference for Somfy's quietest interior range. Order the Somfy Sonesse 40 RTS 406A2 RH with Fast Connector (1240381) with the crown and drive set that matches your tube, and add a Situo remote if the job has no RTS transmitter on site yet.
Shade Motors Direct is an authorized source for genuine Somfy motorized window shade, blind, and drapery parts.
