Somfy motor names look like license plates. 506S2, 525A2, 550R2, 6100R2, 404S2 — they are not arbitrary, and once you can read them you can tell a motor's platform, its strength and roughly its speed without opening a spec sheet.
The structure
A code such as 525A2 breaks into four parts:
- 5 — the platform, matched to tube size
- 25 — the torque in newton-meters
- A — the speed class
- 2 — the generation
So a 525A2 is a 500-series motor delivering 25 Nm at the middle speed band, second generation.
The first digit: platform and tube size
| 4 | 400 series — LS40 / Sonesse 40 platform, roughly 37–38mm minimum tube |
| 5 | 500 series — LT50 / Sonesse 50 platform, 47mm and up. The busiest platform in residential work |
| 6 | 600 series — LT60 platform, 60mm tube, for rolling shutters and large exterior assemblies |
The platform determines which crowns, drives and brackets fit. An LT50 crown will not mount an LT60 motor, and the two platforms share no hardware.
The middle digits: torque in Nm
This is the most directly useful part of the code. Read the digits between the platform number and the letter as the torque rating:
- 506S2 → 6 Nm · 510S2 → 10 Nm · 515S2 → 15 Nm
- 525A2 → 25 Nm · 530R2 → 30 Nm · 535A2 → 35 Nm
- 540R2 → 40 Nm · 550R2 → 50 Nm
- 660R2 → 60 Nm · 680R2 → 80 Nm · 6100R2 → 100 Nm
- 404S2 → 4 Nm · 409R2 → 9 Nm · 412R2 → 12 Nm
Note the 6100R2: three digits, because 100 Nm needs them. The pattern still reads cleanly once you know the first digit is the platform.
The letter: speed class
The letter tracks the speed band. Across the Somfy range as catalogued, it works out consistently:
| S | Fastest band, roughly 30–38 rpm. Light interior shades. Example: 506S2 at 6 Nm / 32 rpm |
| A | Middle band, roughly 20–24 rpm. Example: 525A2 at 25 Nm / 20 rpm |
| R | Slow and strong, roughly 12–14 rpm. Heavy exterior work. Example: 550R2 at 50 Nm / 14 rpm |
The relationship is not a coincidence: within a platform, gearing torque up means gearing speed down. High-torque motors are slow motors.
The trailing digit: generation
The trailing 2 marks the current generation of the platform. Older stock and legacy part numbers may carry different trailing digits; where a product here replaces a discontinued reference, the listing names both part numbers so you can match what you are replacing.
What the code does not tell you
The model code describes the mechanism, not the control system. A 506S2 exists as an RTS version, an RS485/SDN version, and a plain 4-wire wired version, all with identical torque and speed. It also does not tell you the head type — star head versus round head changes which bracket fits.
For those two, the Somfy part number is what matters. Every listing on this site carries the part number in the title, so 1001809 gets you exactly the Sonesse 506S2 RTS and nothing else.
Worked examples
- 506S2 — 500 series, 6 Nm, fast, gen 2. The default interior roller shade motor for 2 in tube. Sonesse 506S2 RTS (1001809)
- 525A2 — 500 series, 25 Nm, mid speed, gen 2. Cassette awnings and zip screens. Maestria 525A2 RTS (1134083)
- 6100R2 — 600 series, 100 Nm, slow, gen 2. Large rolling shutters on 60mm tube.
With the code read, size the motor properly using How to Size a Somfy Shade Motor, then pick a control protocol. Browse all Somfy motors.
