Torque sets this order before anything else. A 15 Nm motor lifts a heavier fabric roll on the same 50mm tube than a 6 Nm motor does, and the Somfy 515S2 RS485 sits near the top of the star head RS485 range for interior work. Somfy publishes 15 Nm at 38 rpm for reference 1002427. Speed carries as much weight as torque on a tall shade, because 38 rpm moves a 12 foot drop in one short cycle.
Buyers arrive at this SKU from two directions. Some size up for a wide commercial roller and land on 15 Nm because the fabric roll got heavy. Others start from the control side, need two-way RS485 feedback into a building system, then pick the torque the fabric demands.
Shades the 515S2 RS485 drives
Somfy names interior window coverings and exterior solar screens for reference 1002427. Projection screens appear on the same application list, which explains a good share of the demand for this torque point. A 120 inch wide screen on a 2.5 inch tube carries real mass once the fabric wraps, and the 250 turn electronic limit capacity covers the drop.
Installers choose this motor for occupied commercial rooms where a control system owns the schedule. Somfy publishes a 55 dB sound level for the reference, which puts it in the standard LT50 range rather than the quieter Sonesse tier. Read the section below on the store listing before you treat this SKU as a Sonesse.
Verified Somfy specifications
Every figure here comes from Somfy's own published data for reference 1002427, cross checked against the LT50 RS485 star head datasheet.
| Reference | 1002427, "515S2 LT RS485 15/38 SJTW3M UN" |
| Torque and speed | 15 Nm (133 in-lb) at 38 rpm |
| Control | RS485 two-way, Somfy Digital Network |
| Power supply | 120V AC, 60 Hz |
| Rated current | 1.8 A |
| Power draw | 210 W running, 0.5 W standby |
| Sound level | 55 dB |
| Protection and class | IP 44, Class I |
| Head type | Star |
| Motor diameter | 1.77 in external, 1.97 in nominal |
| Minimum tube inner diameter | 1.85 in (47 mm) |
| Length | 26.57 in |
| Limit switches | Electronic, 250 turn capacity |
| Cable | SJTW, 9.84 ft |
| Temperature | -4 to 140 F operating, -4 to 176 F storage |
| Thermal protection | 4 min |
| Certification and warranty | UR, 5 years |
Tube, crown and drive fit
The 1.85 inch minimum tube inner diameter governs the whole build. Somfy states the interior tube diameter must exceed 47 mm, and a tube under that measurement will not accept the motor body. Measure the inside of the tube, not the outside, and measure it at the end you plan to insert the motor into.
Two crown and drive sets cover most builds on this platform. The Somfy LT50 2.5 inch Round Crown and Drive Set (9012231) handles round 2.5 inch tube, the common choice for a wide interior roller or a projection screen. The Somfy Octagonal LT50 70mm Crown and Drive Set (9012234) fits 70mm octagonal tube on exterior solar screen and shutter work. Both sets snap to the motor, so no fastener holds the drive in place.
The head needs a bracket cut for a star. Somfy publishes STAR as the head type on this reference, and the Somfy LT50 Star Head Motor Bracket (9410651) takes that head straight. A CMO bracket will not hold a star head, and a star bracket will not hold a CMO crank head. Check the head type on the motor you receive against the bracket before you cut anything.
SDN wiring and addressing
RS485 gives the motor two-way conversation with the control system. The motor reports its position and its limit status back up the bus, so a head end knows where every shade sits rather than guessing from the last command it sent. Somfy builds animeo IP and the wider Somfy Digital Network around that feedback.
Each motor on the bus needs an address. The Somfy RS485 Setting Tool (9017142) reads and writes those addresses at the motor and sets the travel limits without a laptop, which earns its price on a job with 40 shades in a ceiling pocket. For bench work and bulk configuration from SDN Motor Configuration Software, the Somfy USB to RS485 Adaptor for SDN (9015260) puts a laptop on the bus.
Power and data run on separate cables. The 120V supply arrives on the 9.84 foot SJTW pigtail Somfy ships attached to the motor. Somfy sells the data cable on its own, in the length the run needs, so order it against the real distance from the motor to the bus.
Install notes for the 515S2
Set the limits after the fabric hangs. Electronic limits on this reference hold a 250 turn capacity, and the tool or the software writes them. A motor with limits set on the bench and a tube cut later will run past the fabric.
Thermal protection cuts the motor after 4 minutes of continuous duty. That covers any normal shade cycle with room to spare, and it matters during commissioning, when an installer runs one shade up and down 20 times in a row. Give the motor a rest between long test sequences.
Class I insulation means this motor needs a ground. The SJTW pigtail carries the conductor for it. Terminate the ground at the panel rather than capping it in the pocket.
Ordering the 515S2 RS485
The store listing for this motor carries "Sonesse 50" in the title and calls out an "ultra-quiet Sonesse platform" in the benefits. Somfy publishes the reference as "515S2 LT RS485" on the LT50 star head line, at 55 dB. The Sonesse 50 tier runs closer to 45 dB. Same motor, same SKU, same 15 Nm on the same 50mm tube, and the LT50 parts above are the correct fitment either way. Order by the reference number, 1002427, and size the acoustics to the 55 dB figure Somfy publishes. Somfy's own data is the authority here, and we have logged the listing text for correction.
The listing also prints 35 rpm in its spec table. Somfy publishes 38 rpm. Use 38 rpm for any cycle time calculation.
The Somfy 515S2 RS485 SDN 120V Motor (1002427) ships as a bare motor with its SJTW pigtail. Add the crown and drive set that matches your tube, plus a star head bracket. Put the setting tool on the order too if nobody on the crew carries one. Data cable and any SDN gateway hardware go beside them.
Somfy backs the motor for five years, and the RS485 platform has run in commercial buildings long enough that replacement parts stay on the shelf. Genuine Somfy parts keep that warranty intact.
Frequently asked questions
What tube does the Somfy 515S2 RS485 fit?
Somfy publishes a minimum internal tube diameter of 1.85 inches, or 47 mm, for reference 1002427. Any tube with an inside measurement above that figure accepts the motor body. Standard 2.5 inch round tube and 70mm octagonal tube both clear it with the matching LT50 crown and drive set.
How much does the 515S2 RS485 lift?
Somfy rates this motor at 15 Nm, which converts to 133 in-lb, at 38 rpm. Torque translates to lifting capacity through the roll diameter, so a fabric roll that grows larger as the shade rolls up needs more torque at the top of travel. Size the motor against the finished roll, not the bare tube.
Which bracket holds this motor?
Somfy publishes STAR as the head type on reference 1002427, so the motor needs a bracket cut for a star head. The LT50 Star Head Motor Bracket (9410651) takes it. A CMO bracket built for a crank override head will not seat this head, and forcing the fit damages the bracket plate.
Does the 515S2 RS485 work with RTS remotes?
No. This motor carries no radio receiver. Control arrives over the RS485 bus from the Somfy Digital Network or a third party head end that speaks SDN. An RTS remote has nothing to talk to on this reference. Choose an RTS motor when handheld radio control is the requirement.
Shade Motors Direct is an authorized source for genuine Somfy motorized window shade, blind, and drapery parts.
