Motors and power · Rolling Shutter Guide
What size motor does my rolling shutter need?
Size a rolling shutter motor by curtain weight, not square feet. Multiply width by height in inches, times the slat's weight per square foot, divide by 144, add a small margin, then pick the smallest motor whose lift rating on your axle tube clears it. A 10 Nm motor lifts about 33 lb; a 120 Nm about 370 lb.
Key facts
- Curtain weight in lb = width (in) x height (in) x the slat's sizing weight (lb per sq ft) / 144. Roll-A-Shield's sizing weights are 0.92 for 38 mm insulated, 1.11 for 55 mm insulated, 1.14 for 63 mm single-wall and 0.98 for 63 mm perforated slats. Roll-A-Shield data
- Roll-A-Shield sizes the motor as if the curtain were heavier by 5 lb or 5%, whichever is more, then picks the smallest motor whose rating clears that figure. Roll-A-Shield data
- The same motor is rated lower on a bigger tube: a 50 Nm motor is sized to 175 lb on a 60 mm axle but 150 lb on a 70 mm axle. Roll-A-Shield data
- No motor fits a shutter under 22 in wide at the clear opening, and from 22 to just under 24 in only a 10 Nm motor is short enough. Roll-A-Shield data
- Remote, manual-override and solar versions of a motor carry the same lift rating as the plain motor of the same torque; they differ by control, not capacity. Roll-A-Shield data
Applies to: Tubular motors in rolling shutters: Gaposa, Somfy and OZRoll, on 60 mm and 70 mm octagonal axles. Figures are Roll-A-Shield's sizing values for its own 38 mm, 55 mm and 63 mm slats.
How do I work out what my shutter curtain weighs?
Multiply the curtain width by its height in inches, multiply by the slat's weight per square foot, and divide by 144. The formula is weight_lb = width_in x height_in x psf / 144.
The curtain is the moving part, so it is the only weight the motor lifts. Roll-A-Shield uses these sizing weights for its own slats:
| Slat | Sizing weight (lb per sq ft) | Sizing weight (kg per sq m) |
|---|---|---|
| 38 mm insulated | 0.92 | 4.49 |
| 55 mm insulated | 1.11 | 5.42 |
| 63 mm single-wall | 1.14 | 5.57 |
| 63 mm perforated | 0.98 | 4.78 |
These are sizing figures, the values the factory configurator uses to choose a motor, not shipping weights. For curtain weights by size, see how much a rolling shutter weighs.
Which motor lifts how much? (the chart)
Find your curtain weight in the column for your motor brand and axle tube, and read across to the smallest motor that clears it. These are the lift figures Roll-A-Shield sizes to, in pounds:
| Motor torque | Somfy, 60 mm tube | Somfy, 70 mm tube | Gaposa, 60 mm tube | Gaposa, 70 mm tube | OZRoll, 60 mm tube |
|---|---|---|---|---|---|
| 10 Nm | 33 | 30 | 33 | 30 | 30 |
| 20 Nm | 70 | 65 | 70 | 65 | 70 |
| 30 Nm | 100 | 90 | 100 | 90 | — |
| 35 Nm | — | — | — | — | 115 |
| 40 Nm | 135 | 125 | 135 | 125 | — |
| 50 Nm | 175 | 150 | 175 | 150 | — |
| 60 Nm | — | 215 | — | — | — |
| 80 Nm | — | — | — | 265 | — |
| 100 Nm | — | — | — | 350 | — |
| 120 Nm | — | — | — | 370 | — |
A dash means Roll-A-Shield does not fit that motor on that tube. On a 60 mm tube the chart stops at 50 Nm: the Somfy 60 Nm motor and the Gaposa 80, 100 and 120 Nm motors go in a 70 mm tube only. Gaposa says its 80-120 Nm motors need a tube of at least 63 mm and rates them for 70 mm and larger tubes, and Roll-A-Shield's configurator supplies the crown and drive for a Somfy 60 Nm motor only on a 70 mm tube. In practice this never limits a shutter: a curtain heavy enough to need more than 50 Nm is always built on a 70 mm tube. The Gaposa 80 Nm figure on a 70 mm tube, 265 lb, sits just under Gaposa's own chart value of 268 lb for a shutter 2.5 m tall. OZRoll battery motors always run on a 60 mm tube.
How much margin should I leave?
Roll-A-Shield sizes as if the curtain weighed 5 lb or 5% more, whichever is larger. A small curtain gets the 5 lb floor; above 100 lb the 5% takes over, so a heavy curtain keeps proportional headroom as it approaches a motor's limit.
Three worked examples, using the chart above:
| Shutter | Curtain weight | Sized as | Tube | Smallest motor that clears it |
|---|---|---|---|---|
| 60 in wide x 72 in tall, 38 mm insulated | 27.6 lb | 32.6 lb | 60 mm | 10 Nm (33 lb) |
| 120 in wide x 96 in tall, 63 mm single-wall | 91.2 lb | 96.2 lb | 60 mm | 30 Nm (100 lb) |
| 180 in wide x 120 in tall, 55 mm insulated | 166.5 lb | 174.8 lb | 70 mm | Gaposa 80 Nm (265 lb) or Somfy 60 Nm (215 lb) |
The third shutter needs a 70 mm tube because it is wider than 144 in, and on a 70 mm tube a 50 Nm motor is rated only to 150 lb.
Which axle tube does my shutter have?
The tube is chosen before the motor, from the slat, the operator and the curtain weight.
| Shutter | Axle tube |
|---|---|
| Motorized, 38 mm insulated | 60 mm |
| Motorized, 55 mm insulated | 60 mm up to 140 lb and 144 in overall width; otherwise 70 mm |
| Motorized, 63 mm single-wall | 60 mm under 100 lb; 70 mm at 100 lb and over |
| OZRoll battery motor, any slat | 60 mm |
On an existing shutter, the parts of a rolling shutter page shows where the axle sits, and inside a tubular motor explains the crown and drive that match a motor to its tube.
Does a remote, override or solar motor change the size?
No; the control type changes what you can buy, not the rating.
- Remote (radio) motors carry the same figures as wired motors of the same torque.
- Manual-override motors also carry the same figures. On Roll-A-Shield's configurator, Somfy override motors run from 30 to 60 Nm, and Gaposa override motors run up to 100 Nm wired or 120 Nm with a radio receiver; as with every motor over 50 Nm, these go on a 70 mm tube. See what a manual override is.
- Solar motors come in 30 Nm and 50 Nm only, so the heaviest solar shutter is the one a 50 Nm motor can lift: 175 lb on a 60 mm tube, 150 lb on a 70 mm tube. See how solar shutters work.
- OZRoll battery motors stop at 35 Nm, 115 lb, and suit smaller, lighter shutters.
What about very small shutters?
Below 22 in wide at the clear opening no motor can be fitted, and from 22 in to just under 24 in only a 10 Nm motor is short enough. From 24 in clear, about 28 in overall, any motor size fits. OZRoll battery motors are not bound by this floor. The smallest shutter page covers manual options for narrow windows.
Can I go manual instead?
Only on light curtains. Strap and crank operators are capped at about 50 lb of curtain, and an opening over about 12 ft wide or a curtain of about 100 lb or more has to be motorized. See how big a manual shutter can be.
What next
To check a replacement motor against your shutter, have the width, height, slat type and the old motor's label to hand and call (480) 921-0200. Motor specs by model are on the motor specs page; the motor page compares Gaposa and Somfy, and replacement motors are in the parts store. For a new shutter, request a quote and the factory sizes the motor for you.
Frequently asked questions
Why not size the motor by square feet?
Because two shutters of the same area can weigh very different amounts: a 63 mm single-wall slat is about a quarter heavier per square foot than a 38 mm insulated slat. The square-foot ranges printed in some Somfy model names are labels, not a selection rule.
How much can a 30 Nm motor lift?
Roll-A-Shield sizes a 30 Nm Somfy or Gaposa motor to 100 lb on a 60 mm axle and 90 lb on a 70 mm axle, before the 5 lb or 5% margin is taken off.
Do solar motors lift less than wired ones?
No; a solar motor carries the same rating as a wired motor of the same torque. The limit is choice: Roll-A-Shield builds solar shutters on 30 Nm and 50 Nm Gaposa motors only, so a curtain heavier than the 50 Nm rating needs a wired or remote motor.
My shutter has an old motor. Should the new one be the same size?
Start from the old motor's label, then check it against the curtain weight. On Gaposa motors the model code carries the torque: XQ5EZ3016 is a 30 Nm motor. If the curtain weight has crept close to that rating, call (480) 921-0200 before ordering.
Parts and next step
Need a part or a hand?
Replacement motors, remotes, straps, slats and hardware ship from our Tempe, Arizona factory. Phoenix-area owners can book a service visit; everywhere else, our technicians help by phone. Call (480) 921-0200; the factory answers technical questions for any rolling shutter, not only ours.