Tube inner diameter decides whether the Sonesse 40 WT 409R2 goes into your shade. Somfy builds this motor on the 40 mm Sonesse platform and publishes a 38 mm minimum interior tube diameter for the range. Measure the inside of the tube first. A tube below that figure will contact the motor body and bind the roll.
The 409R2 tops the Sonesse 40 WT torque range at 9 Nm, and Somfy pairs that torque with a 14 rpm output. Installers reach for it when fabric weight and shade width put more load on the tube than the 4 Nm 404S2 or the 6 Nm 406A2 will carry. Somfy terminates this reference with a Fast Connector, so the power hookup takes seconds at the bracket. You can buy the Somfy Sonesse 40 409R2 WT motor (1240379) on its own and add the tube hardware around it.
Shades the 409R2 WT drives
Somfy publishes two application groups for this reference: interior window coverings, and projection screens. The 9 Nm rating covers wide interior roller shades on a 40 mm tube and front-projection screens in a conference room or a home theater. Blackout and dim-out fabrics add weight across a long drop, and the 409R2 carries that load where a 4 Nm motor would struggle. Sound level sits at 40 dB on the Sonesse 40 WT line, which is what puts these motors in bedrooms and boardrooms.
The WT designation marks the wired standard control path. You run this motor from a maintained wall switch, a dry contact relay, or a shade controller channel that switches line voltage. No radio board sits inside the 409R2 WT, so an RTS remote will not drive it. Buyers who want handheld radio control pick the Sonesse 40 RTS line instead.
Verified Sonesse 40 WT 409R2 specifications
| Specification | Published value |
|---|---|
| Somfy reference | 1240379 |
| Somfy product name | Sonesse 40 WT 409R2 RH with Fast Connector |
| Torque | 9 Nm (79.7 in-lb) |
| Speed | 14 rpm |
| Power supply | 120 V AC, 60 Hz |
| Rated current | 0.98 A |
| Power consumption | 120 W |
| Standby consumption | 0.46 W |
| Sound level | 40 dB |
| Protection rating | IP 44 |
| Head type | Round head (RH) |
| Minimum tube inner diameter | 38 mm or greater |
| Limit switch | Progressive adjustment (PA) |
| Limit turns | 40 |
| Cable | 4-conductor Fast Connector pigtail, 0.5 m (1.64 ft) |
| Operating temperature | 32 to 140 F |
| Thermal protection | 4 minutes |
| Applications | Interior blinds and shades, projection screens |
| Approval | UR |
| Warranty | 5 years |
Figures above come from Somfy's published data for reference 1240379 and the Somfy 400 Series Databook. Torque of 9 Nm converts to 79.7 in-lb, and that is the number to carry into a load calculation.
Crown and drive sets for a 40 mm tube
The motor spins a drive wheel, and the drive wheel keys into the tube. Somfy sizes those parts by tube profile, so the tube you pick settles the crown and drive you order. A 40 mm octagonal tube takes the Somfy LS40 octagonal rubberized crown and drive set (9016655), and the rubberized seat damps the start and stop so the roll runs quieter. Round 40 mm tubes take the LS40 rubberized crown and drive set (9016654). Installers who want the standard hard set order the Somfy LS40 crown and drive set (9012224).
Buyers cutting a fresh tube order the Somfy 40 mm octagonal tube (1781154) by the foot. That tube clears the 38 mm figure, so the motor body passes through without contact. Measure the finished opening, subtract your bracket stack, and cut the tube to that length.
The 409R2 WT carries a round head, which Somfy marks RH in the product name. Pick the bracket that accepts a round head on this platform. A star-head plate will not seat a round-head motor.
Fast Connector wiring and power
Somfy terminates this reference with a Fast Connector on a 0.5 m pigtail, four conductors, which is 1.64 ft of cable at the motor head. The connector mates to a matching Fast Connector lead, and the installer makes the joint by hand with no tools. Long runs back to the panel ride on the mating lead rather than on the motor pigtail, which keeps the motor itself short enough to drop into a pocket.
Power comes in at 120 V AC, 60 Hz. The motor draws 0.98 A rated and 120 W in operation, and it settles to 0.46 W at rest. A standard WT motor takes three live conductors, up, down, and common, plus ground. Switch the up and down legs from a maintained switch or a relay contact. Never bridge both legs at once.
Thermal protection cuts in after 4 minutes of continuous run. That window covers a full travel on any interior shade, and it protects the winding on a stalled roll. Wait for the motor to cool before you resume.
Setting progressive adjustment limits
Somfy fits the 409R2 WT with progressive adjustment limits and publishes 40 limit turns for the mechanism. You set the stops with the two adjustment screws on the motor head, and each screw owns one direction. Run the shade toward a stop, hold the travel, and turn the screw to move the stop in small increments. The motor records the position mechanically, so a power cut leaves your limits intact.
Count the turns between your stops before you commission the shade. A drop that needs more than 40 turns of the tube exceeds what the limit mechanism holds, and a taller opening calls for a larger tube diameter to cut the turn count. Secure the fabric to the tube with Somfy's motor screw at the drive end so the roll cannot creep off the keyway during travel.
Ordering the 409R2 WT and the parts around it
Order the motor, the crown and drive for your tube profile, and the bracket that fits your round head. Shade Motors Direct ships the Somfy Sonesse 40 409R2 WT motor (1240379) with the Fast Connector already terminated, so you add the mating lead and the hardware that matches your tube. Buyers running several shades on one controller order the same crown and drive across the job to keep the install repeatable.
Somfy backs this motor for 5 years and lists it under UR approval. The 9 Nm rating gives you headroom on a wide interior shade, and the 40 dB sound level keeps the motor quiet in a room where people work or sleep.
Frequently asked questions
What size tube does the Somfy 409R2 WT fit?
Somfy publishes a minimum interior tube diameter of 38 mm for the Sonesse 40 range, and the 409R2 WT follows that figure. A 40 mm octagonal or round tube accepts the motor with clearance. Measure the inside of the tube, not the outside, because wall thickness varies between tube suppliers.
Will an RTS remote control the 409R2 WT motor?
No. The WT reference carries no radio receiver, and Somfy drives it from a wired control path at 120 V AC. You operate it from a maintained wall switch, a dry contact relay, or a shade controller channel. Buyers who want handheld radio control choose a Sonesse 40 RTS motor instead.
How much torque does the Sonesse 40 409R2 deliver?
Somfy rates this motor at 9 Nm, which converts to 79.7 in-lb, with an output speed of 14 rpm. That rating tops the Sonesse 40 WT range above the 4 Nm 404S2 and the 6 Nm 406A2, and it suits wide interior roller shades and projection screens on a 40 mm tube.
What does the Fast Connector change on this motor?
Somfy terminates the 409R2 WT with a 0.5 m four-conductor pigtail ending in a Fast Connector. The installer mates it to a matching lead by hand, with no stripping and no wire nuts at the bracket. Power still arrives at 120 V AC, 60 Hz through that connection.
Shade Motors Direct is an authorized source for genuine Somfy motorized window shade, blind, and drapery parts.
