Installers reach for the Somfy Sonesse 40 RS485 406A2 when a building runs its shades on a wired bus rather than radio. Somfy builds this one around 6 Nm of lifting torque at 24 rpm, inside a 40mm tube, with two-way RS485 communication on the Somfy Digital Network. The reference number is 1240563.
Tube diameter decides this motor first
Somfy publishes a 37 mm minimum internal tube diameter for the 406A2, with a 40 mm motor body. Standard 1.5 inch and 2 inch roller tubes clear that figure. Measure the inside of the tube rather than the outside, because a heavier wall on a nominal 1.5 inch tube can close the gap that the motor needs.
Length matters as much as diameter. Somfy lists the motor at 545 mm (21.46 in) unwrapped, with the riveting position at 514 mm (20.24 in). Take that length out of the shade width, add the idler end and both brackets, and the remainder is your tube cut. Fabricators who skip that subtraction end up trimming a tube twice.
Shades the 406A2 lifts
Six newton meters covers interior roller shades through the middle of the 400 Series range. A blackout roller on a tall bedroom window sits inside that band, and a wide office screen does too. Somfy rates the motor IP 31 with Class II insulation, which places it indoors on interior fabric.
Somfy offers the same 40mm RS485 platform at three torque points. The 404S2 turns 4 Nm at 36 rpm for smaller shades that want travel speed. The 406A2 holds the middle at 6 Nm and 24 rpm. The 409R2 climbs to 9 Nm at 14 rpm for the widest or heaviest fabric in the series. Pick by the weight of the finished roll, then confirm the speed suits the room.
The round head keeps the fascia line clean, and Somfy supplies head covers in white, black, and grey to match the hardware around it.
Torque headroom protects the motor over years of cycling. A roll that sits near the ceiling of a motor's rating draws more current on every start and works the thermal cutout harder. Somfy's 4 minute thermal protection time on the 406A2 tells you the duty cycle the engineers designed around. Size the motor so the shade never leans on that limit, and the warranty period passes without a service call.
Verified specifications
| Torque | 6 Nm (53 in-lb) |
| Speed | 24 rpm |
| Control | RS485, Somfy Digital Network |
| Supply voltage | 120V AC, 60 Hz (108 to 132 V) |
| Rated current | 0.95 A |
| Power in operation | 114 W |
| Standby power | 0.5 W |
| Sound level | 44 dB |
| Protection index | IP 31 |
| Insulation class | Class II |
| Minimum tube internal diameter | 37 mm (1.46 in) |
| Motor diameter | 40 mm (1.57 in) |
| Motor length, unwrapped | 545 mm (21.46 in) |
| Riveting position distance | 514 mm (20.24 in) |
| Cable | SVT, 0.5 m (1.64 ft), Fast Connector |
| Head shape | Round |
| Operating temperature | 32 to 140 F |
| Storage temperature | -4 to 167 F |
| Thermal protection | 4 min |
| Weight | 1.3 kg (2.87 lb) |
| Warranty | 5 years |
Every figure above comes from Somfy's published record for reference 1240563.
Crown and drive parts for a 40mm tube
A tubular motor transmits torque through a drive wheel at the head and rides on a crown at the body. Match both to the tube profile you ordered. For round 40mm tube, the Somfy LS40 Rubberized Crown and Drive Set (9016654) seats the motor and damps the buzz that a bare metal fit passes into the tube. For octagonal tube, order the Somfy LS40 Octagonal Rubberized Crown and Drive Set (9016655) instead. Both sets carry the rubberized surface, which earns its keep on a quiet shade in an occupied room.
On the bracket side, Somfy publishes motor plates and universal brackets for the 400 Series head, including adapters for RollEase SkyLine hardware. Confirm the bracket you already stock accepts a round head at 40mm before the shipment lands, since a plate mismatch stops an install cold.
Wiring and commissioning on the Somfy Digital Network
Somfy ships the 406A2 with a 0.5 m SVT lead terminated in a Fast Connector, and sells extension cables from 1.4 ft through 24 ft so a run reaches the junction without a splice. Plan the cable length at layout time. A shade pocket that swallows the connector leaves no room for a tester later.
Every motor on an SDN bus carries its own address. The Somfy RS485 Setting Tool (9017142) reads and writes those addresses at the motor, which suits a punch list or a single replacement on a floor that already works. For a whole building, the Somfy USB to RS485 Adaptor for SDN (9015260) puts the bus on a laptop so an integrator can address, set limits, and check status from Somfy's software.
Somfy powers the 406A2 from a 120V AC supply at 60 Hz, with a tolerance band from 108 V to 132 V. Long branch circuits in a tall building can sag toward the bottom of that band under load, and an electrician who checks voltage at the last motor on the run catches the problem before the shades do. Rated current sits at 0.95 A, so a circuit carries a useful number of motors before the panel schedule forces a second one.
The 0.5 W standby figure repays attention on a large project. Two hundred motors idle at 100 W across a building, which shapes the circuit schedule and the energy model an engineer files.
Ordering the 406A2 and the parts around it
Order the motor, the crown and drive that matches your tube, and one commissioning tool per crew. The Sonesse 40 RS485 406A2 carries Somfy's 5-year warranty, and the RS485 platform gives an owner a documented upgrade path into animeo IP and building management long after the shades hang.
Buyers who need more lift on the same wired bus should look at the 409R2 at 9 Nm. Buyers whose project runs on radio instead should look at the Sonesse 40 RTS line, which shares the tube fit and the head shape.
Frequently asked questions
What tube size does the Sonesse 40 406A2 need?
Somfy publishes a 37 mm minimum internal tube diameter, with a motor body of 40 mm. Standard 1.5 inch and 2 inch roller tubes accept it. Measure the internal diameter of the tube you plan to use, because wall thickness varies between suppliers on the same nominal size.
How loud is the Sonesse 40 RS485 motor?
Somfy rates the 406A2 at 44 dB. A rubberized crown and drive set holds that figure in the field by keeping metal-to-metal contact out of the tube. Hotel rooms, offices, and conference spaces all sit inside that noise budget with the motor mounted on a solid bracket.
Can the 406A2 run on RTS remotes?
No. This motor communicates over RS485 on the Somfy Digital Network, with no radio receiver inside it. Somfy builds a full Sonesse 40 RTS range for projects that want handheld remotes, and those motors share the same tube fit and round head. Choose the control platform before you order the motor.
What separates the 404S2, 406A2, and 409R2?
Torque and speed. The 404S2 delivers 4 Nm at 36 rpm, the 406A2 delivers 6 Nm at 24 rpm, and the 409R2 delivers 9 Nm at 14 rpm. All three share the RS485 platform, the 40mm body, and the round head, so crown, drive, and bracket choices carry across the range.
Shade Motors Direct is an authorized source for genuine Somfy motorized window shade, blind, and drapery parts.
