Thirty five decibels is the number that sells this motor. That is quieter than a refrigerator across a kitchen, and it is what a bedroom or a screening room asks for when a shade moves at six in the morning. The Somfy Sonesse Ultra 504A8 RTS 24V DC (1134023) gets there by running on low voltage rather than on line power.
Somfy lists it for interior window coverings and projection screens, at 4 Nm and 25 rpm with an RTS receiver built in. It carries an IP20 rating, so it belongs indoors.
Low voltage changes what the electrician does
The motor runs on 24V DC, with Somfy publishing a working range of 22.8V to 25.2V and a rated current of 1.5 A. Power arrives from a transformer or a distribution panel rather than from a branch circuit at the opening.
That narrow voltage window is the part worth respecting. A long run of thin conductor drops voltage along its length, and a motor at the far end of a fifty foot run on undersized wire can sit below 22.8V under load. Size the conductor for the run rather than for the connector.
The upside on a retrofit is real. Low voltage cable is easier to route through a finished ceiling than line voltage, and in many jurisdictions the rules for running it are lighter. Confirm what applies locally before planning the route.
Verified specifications
| Torque | 4 Nm (35 in-lb) |
| Speed | 25 rpm |
| Noise | 35 dB |
| Power supply | 24V DC, range 22.8V to 25.2V |
| Rated current | 1.5 A |
| Consumption | 36 W running, 0.48 W standby |
| Control | RTS, built-in receiver, 433.420 MHz |
| Channels | 12 |
| Radio range | 656.2 ft open field, rolling code |
| Minimum tube inside diameter | 1.85 in |
| Motor outside diameter | 1.77 in |
| Head type | Square |
| Limits | Electronic, 38 turn capacity |
| Ingress rating | IP20, indoor |
| Insulation class | Class III |
| Operating temperature | 32 F to 140 F |
| Weight | 5.51 lb |
| Warranty | 5 years |
Figures come from Somfy's published product record for 1134023. Somfy also publishes a 49.9 kg CO2 lifecycle footprint.
The square head needs its own bracket
Somfy builds this motor with a square head rather than the star head found across the AC side of the Sonesse 50 range. A star bracket will not hold it.
The part to order is the Somfy Sonesse Ultra 50 DC Motor Bracket with Spring Ring (9020957). The spring ring takes up the small movements that would otherwise transmit into the mounting surface, which protects the quiet the motor was bought for.
Shops that stock AC Sonesse hardware and order this motor without checking the head end up holding a bracket that does not fit. Put the bracket on the same purchase order.
Soft clip drive for a quiet install
The drive train has a quiet option too. A Somfy LT50 2.5" Soft Clip Drive (9206041) pairs with the Somfy LT50 2.5" Crown (9707026) on a 2.5 in tube, and the soft clip damps the mechanical noise a hard clip passes into the tube wall.
On a 50 mm profiled tube the equivalent is the Somfy Sonesse 50 Drive Wheel 50mm x 1.5mm Soft Clip (9018455). Specifying a hard clip on a 35 dB motor gives back some of what was paid for.
Minimum tube inside diameter is 1.85 in against a motor body of 1.77 in, the same as the AC motors in the range, so tube selection carries across.
Thirty eight turns of limit capacity
Somfy publishes 38 turns between the open and closed stops, which is a lower number than the 250 turns on the AC motors and needs a moment of arithmetic.
A 2.5 in tube pays out roughly 8 in of fabric per revolution once the roll builds, so 38 turns covers something on the order of 25 ft of drop. Interior shades and projection screens sit well inside that. A tall atrium shade is the case to check against the fabricator's roll-up calculation before ordering.
At 25 rpm a ten foot shade takes about forty seconds. Slower than the 32 rpm AC motors, and in a bedroom the slower travel reads as calm rather than as waiting.
Powering more than one shade
A single shade runs from the Somfy 24V DC 1.67 Amp Plug-in Wall Mount Transformer (1822209), which covers the motor's 1.5 A draw with a little margin.
A bank of shades takes a distribution enclosure instead. The Somfy 24v Power Distribution Enclosure for 5 Motors (1870196) feeds five motors from one supply and puts the power in a serviceable box rather than behind five separate plug-in transformers.
Size the supply from the worst case, which is every shade moving on the same command at 1.5 A each. Standby is 0.48 W per motor, so the resting load is small next to the moving load.
Ordering
Order the Sonesse Ultra 504A8 RTS (1134023) with the DC bracket cut for a square head, a soft clip crown and drive matched to the tube, and a 24V supply sized for the number of motors on the run. Add an RTS transmitter such as the Somfy Situo 5 Channel RTS Pure Remote (1870575) for commissioning. Somfy covers the motor for 5 years.
Questions we get on this motor
How much quieter is the DC motor than the AC version?
Somfy publishes 35 dB for this motor against 47.2 dB for the AC Sonesse 510S2. Decibels are logarithmic, so that gap reads as a large drop by ear rather than a small one. Pair it with a soft clip drive and the spring ring bracket to keep the mechanical path quiet as well.
What bracket does the 504A8 need?
A bracket cut for a square head. Somfy builds this motor with a square head rather than the star head on the AC side of the Sonesse 50 range, and the Sonesse Ultra 50 DC Motor Bracket with Spring Ring (9020957) is the part built for it.
How many shades will one transformer run?
The plug-in 1.67 A transformer suits a single motor drawing 1.5 A. For several shades, use a 24V distribution enclosure sized for every motor moving at once rather than for their resting draw. Watch conductor size on long runs, since the motor's working range stops at 22.8V.
Can this motor go in a bathroom or outdoors?
No. Somfy rates it IP20 and lists interior window coverings and projection screens as its applications. A wet or exterior opening wants an IP44 motor such as an Altus RTS or a Sonesse 50 AC motor.
Shade Motors Direct is an authorized source for genuine Somfy motorized window shade, blind, and drapery parts.
