A 35 Nm tubular motor earns its place on the wide awnings and exterior screens that a 6 Nm interior motor will never move. The Somfy Altus RTS 535A2 sits in the middle of the LT50 range at 35 Nm and 20 rpm, with the radio receiver built into the motor head. Installers reach for this reference when the fabric is wide, the tube measures 1.85 in or more across the inside, and running control wire back to a switch box makes no sense.
The Somfy 535A2 Altus RTS 120V 3-Wire Motor carries reference 1038168 in Somfy's catalog, and Somfy publishes it as the Altus RTS 535A2.
Torque and tube diameter decide the fit
Two figures settle most Altus RTS specifications before anyone opens a box. Somfy rates this motor at 35 Nm, which converts to 310 in-lb, and the motor needs a tube with a minimum internal diameter of 1.85 in. The motor body measures 1.77 in across and 26.89 in long with the cable unwrapped, so the tube has to clear that length plus the crown and drive stack at each end.
Torque headroom matters on exterior fabric. A retractable awning loads the tube hardest at the moment of takeoff, and wind pressure on a zip screen adds load through the whole travel. Somfy builds the 500 Series in torque steps for that reason, and the 535A2 covers the band above the 30 Nm 530R2 and below the 40 Nm 540R2.
Shades, awnings and screens this motor drives
Somfy lists six applications for reference 1038168. Awnings and rolling shutters take the largest share of Altus RTS installs, and the same motor serves exterior solar screens, retractable insect screens, projection screens, and interior window coverings. The 56 dB sound level and the IP 44 rating point the 535A2 at exterior work and at interior rooms where fabric size outweighs quiet running.
Interior rooms that need library quiet call for a Sonesse or Sonesse ULTRA motor instead. The Altus RTS trades acoustic polish for torque and weather sealing, and that trade suits a 14 ft lateral arm awning.
Verified Altus RTS 535A2 specifications
| Specification | Published figure |
|---|---|
| Somfy reference | 1038168, 535A2 ALTUS RTS 35/20SJTW 10FT |
| Rated torque | 35 Nm (310 in-lb) |
| Rotation speed | 20 rpm |
| Power supply | 120V AC, 60 Hz |
| Rated current | 2.1 A |
| Power consumption | 250 W running, 0 W standby |
| Radio | RTS, 433.420 MHz, 12 channels, rolling code |
| Radio range | 656.2 ft open field |
| Sound level | 56 dB |
| Ingress protection | IP 44, Class I |
| Motor head | Star |
| Limit switches | Electronic, 250 turn capacity |
| Minimum internal tube diameter | 1.85 in |
| External diameter | 1.77 in |
| Length, cable unwrapped | 26.89 in |
| Cable | SJTW, 9.84 ft |
| Operating temperature | -4 F to 158 F |
| Storage temperature | -4 F to 176 F |
| Thermal protection | 5 min |
| Approval and warranty | UR, 5 years |
Figures come from Somfy's own e-catalogue entry for reference 1038168.
Crowns, drives and the star head bracket
The star head governs which bracket holds this motor. A star head seats in a bracket cut for that profile, and a round head bracket will not take it. Order the Somfy LT50 Star Head Motor Bracket (9410651) for a fixed star mount.
The drive end depends on the tube profile. For 2.5 in round tube, the Somfy LT50 2.5" Round Crown and Drive Set (9012231) matches the crown to the tube wall and snaps the drive onto the motor shaft. For 70 mm octagonal tube, common on rolling shutters and older awning barrels, the Somfy Octagonal LT50 70mm Crown and Drive Set (9012234) carries the matching octagonal crown. Measure the tube inside diameter and identify the profile before ordering either set, since the crown has to sit flush in the tube and the drive has to key onto the motor.
Use LT50 parts on this motor. LT60 crowns and drives and LS40 hardware belong on different motor diameters and will not seat.
RTS pairing and control
The receiver lives inside the motor, so nothing sits between the motor and the fabric except the crown and drive. Somfy runs RTS at 433.420 MHz with a rolling code and 16 million code possibilities, and the motor holds up to 12 channels. That channel count sets the ceiling on how many separate controls one motor answers.
The Somfy Situo 1 Channel RTS Pure Remote (1870571) gives one shade its own handheld control and doubles as the programming transmitter for first pairing. Multi-channel Situo and Telis remotes group several motors under one handset. Sun and wind sensors in the RTS family send their own commands to the same receiver, which keeps an awning retracting on a gust without a hub. A TaHoma hub adds app and voice control on top, and the motor keeps answering the remote either way.
This motor answers radio commands. Its three power conductors carry line voltage only, so a maintained wall switch wired into the supply has no path to the motor logic. RTS wall switches and handheld remotes cover wall control for this reference.
Limit setting and install notes
The 535A2 uses electronic limits with a 250 turn capacity, which covers tall rolling shutters and long awning projections without a gearbox change. Set limits with the programming remote after the motor sits in the tube and the fabric hangs, since the upper limit depends on where the hem bar or hood closes.
Four points save a callback:
- Confirm tube internal diameter before ordering, and confirm the profile at the same time. The 1.85 in minimum is the floor, not a target.
- Leave the SJTW pigtail accessible. Somfy supplies 9.84 ft, and a junction inside a closed hood invites a service call.
- Give the motor a thermal margin. Somfy publishes 5 min of continuous run before thermal protection cuts in, which suits normal cycles and rules out repeated testing back to back.
- Record the motor direction before final assembly. Reversing a star head motor in a finished hood costs more time than checking at the bench.
Somfy backs reference 1038168 with a 5 year warranty, and the UR approval covers the 120V 60 Hz supply the motor ships for.
Frequently asked questions
What tube does the Somfy Altus RTS 535A2 fit?
Somfy publishes a minimum internal tube diameter of 1.85 in for reference 1038168. The motor body measures 1.77 in across and 26.89 in long with the cable unwrapped. Pair it with LT50 crowns and drives cut for the tube profile in hand, either 2.5 in round or 70 mm octagonal.
How much weight will 35 Nm lift?
Torque and lift capacity depend on tube diameter, since a larger tube gives the motor a longer lever arm and reduces the load it will raise. Somfy rates the 535A2 at 35 Nm, or 310 in-lb, at 20 rpm. Size from the finished fabric weight, the tube diameter, and the drop.
Does the 535A2 need a separate RTS receiver?
No. Somfy builds the RTS receiver into the motor head, so the motor pairs straight to a Situo or Telis remote with no external receiver. The motor holds up to 12 channels at 433.420 MHz with rolling code security, and RTS sun and wind sensors talk to the same receiver.
Which bracket suits a star head motor?
Use a bracket cut for the star profile, such as the Somfy LT50 Star Head Motor Bracket (9410651). A round head bracket will not hold a star head, and a CMO bracket serves the override versions of the 500 Series. Check the head profile on the motor in hand against the bracket before mounting.
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