A rolling shutter stops moving at the point where torque runs out. Installers size past that point, and on the LT50 frame the Somfy 550R2 sits at the heavy end of the wired range.
Large closures point to 50 Nm
Somfy names this motor 550R2 50/14 SJTW, and the name carries the rating. The 5 marks the LT50 frame, 50 gives the torque in newton meters, and 14 gives the output speed in rpm. A buyer who reads the part number already knows the two figures that decide fit.
The 550R2 drives large rolling shutters, wide exterior screens, and awnings built on LT50 tube. Weight and width both push torque demand up. A 20 Nm or 35 Nm LT50 motor runs a bedroom shutter without strain, then stalls or overheats under a commercial slat curtain twice that size. Somfy covers the gap with the 550R2 and its 50 Nm output.
Speed matters on tall openings. At 14 rpm the tube turns slower than a 20 rpm screen motor, which trades travel time for pulling power. On a 10 foot shutter that reads as a steady, controlled run rather than a rush.
This is the wired model. It carries no radio receiver, so it answers to a wall switch, a relay, or a building control panel. Somfy builds RTS and CMO versions of the same 550R2 for installers who need radio control or a manual crank override, and the specification sheet for each sits on the Somfy Pro product page.
Verified specifications for the Somfy 550R2
Every figure below comes from Somfy's published record for part 1051464 and from the 500 Series Databook.
| Official Somfy name | 550R2 50/14 SJTW |
| Part number | 1051464 |
| Torque | 50 Nm (440.1 in-lb) |
| Speed | 14 rpm |
| Motor frame | LT50, 500 Series |
| Power supply | 120V AC, 60 Hz |
| Consumption in operation | 250 W |
| Standby consumption | 0 W |
| Head type | Star, standard 4-wire |
| Control | Wired, 4-wire, no radio receiver |
| Limit type | Mechanical, rapid-adjustment push buttons |
| Cable | SJTW, 4-wire |
| Protection rating | IP 44 |
| Warranty | 5 years |
The 0 W standby figure deserves a second look on a multi-shutter job. Twenty wired LT50 motors draw nothing between runs, which keeps a large facade off the standby load calculation.
The crown and drive set the tube fit
The motor body slides inside the tube. Two parts bridge the gap: a crown at the head end, which locates the motor inside the tube, and a drive at the output end, which transfers rotation to the tube wall. Match both to the tube on your bench.
Measure the inside diameter and identify the profile before ordering. Octagonal shutter tube, round screen tube, and deep shutter profile all take different sets. Four sets cover most LT50 work:
- The Somfy LT50 DS78MM Crown/Drive Set (9012239) fits 78mm deep shutter tube, the profile under most North American rolling shutter curtains.
- An octagonal 60mm set covers the narrow European shutter tube that arrives on imported systems.
- An octagonal 70mm set handles the wider version of that same profile.
- The Somfy LT50 2.5" Crown (9707026) pairs with the Somfy LT50 2.5" Hard Clip Drive (9206019) on 2.5 inch round tube, a common exterior screen size.
Order the crown and the drive together. A crown that fits the tube with a drive that does not leaves the motor spinning inside its own housing, and the shade never moves.
Bracket choice follows the head
The 550R2 carries a star head, so the bracket has to accept a star. The Somfy LT50 Star Head Motor Bracket (9410651) takes the head straight into a matching socket and holds torque reaction at the wall or the shutter box. A CMO head from a crank-override motor will not seat in it, and a star head will not seat in a CMO bracket. Check the head against the bracket on the bench, not on the ladder.
Shutter boxes built to tight tolerances sometimes need a shallower mount. The LT50 universal bracket with spring clip gives a second option where the star bracket runs out of clearance. Both hold the head; the choice comes down to the pocket in front of you.
Wiring and limit setup
Four conductors leave the motor in an SJTW jacket: line, neutral, up, and down. Energize up or down and the tube turns. Hold both at once and nothing should happen, which is why a proper shade switch interlocks the two directions. Use a Somfy-rated wired switch, a dry-contact relay module, or a motor controller with interlocked outputs.
Radio remotes stay out of this circuit. No receiver sits inside the 550R2, so a Telis handheld or a DecoFlex wireless switch has nothing to pair with. Add radio by feeding the motor from an RTS receiver upstream, or order the 550R2 RTS model and get the receiver built in.
Limits run on mechanical rapid-adjustment buttons at the head. An installer sets the up stop and the down stop by driving the shutter to each end and adjusting the buttons until the travel lands where the opening needs it. Set limits before the curtain carries its full weight, then confirm both ends under load. The LT50 RA spec sheet and the 500 Series Databook on the product page give the exact button sequence for the head in your hand.
One more check at commissioning. Run the shutter end to end twice, listen for the drive seating in the tube, and confirm the motor reaches each stop without pressing into it. A limit set a turn too far works on day one and wears the end stop by year three.
Order the motor with its parts
The Somfy 550R2 120V 4-Wire Motor (1051464) ships as a motor. Tube hardware and the bracket ship as their own line items, and a job stalls on the loading dock when one of them goes missing from the order.
Build the line items in this order: motor, crown and drive set matched to the tube, star head bracket, idler end of the assembly, and the wired switch or relay that will drive it. Confirm the connector on the motor you receive before you buy a pigtail or an extension, since cable ends vary across production runs.
Somfy backs the 550R2 with a 5 year warranty and a parts ecosystem that has stayed consistent across the LT50 range for two decades. An LT50 crown bought today seats in an LT50 motor bought years ago, and that continuity is the reason shops keep the 500 Series on the shelf.
Frequently asked questions
Which tube does the Somfy 550R2 fit?
The motor fits any LT50 tube with a matching crown and drive set. Somfy builds sets for 78mm deep shutter profile, 60mm and 70mm octagonal shutter tube, and 2.5 inch round tube. Measure the inside diameter of your tube and identify the profile, then order the set that matches both.
Can the 550R2 pair with an RTS remote?
This version carries no radio receiver, so it cannot pair with a Telis remote or a DecoFlex wireless switch. Control comes from a wired switch or a relay. Somfy offers the 550R2 RTS with the receiver built into the motor, and that model pairs with the full RTS remote range.
What separates the 550R2 from the 550R2 CMO?
Torque and speed match at 50 Nm and 14 rpm. The CMO version adds a crank manual override, so a user can move the shutter by hand during a power outage. The two heads differ, and a CMO motor needs a CMO bracket rather than the star bracket used here.
Does the 550R2 need a dedicated circuit?
The motor draws 250 W in operation on 120V, 60 Hz, and 0 W at rest. Several motors share a circuit on most residential jobs. Total the running load for every motor that can travel at the same time, then size the circuit and the relay contacts to that number.
Shade Motors Direct is an authorized source for genuine Somfy motorized window shade, blind, and drapery parts.
