When I select a tubular motor, I do not begin with the motor’s advertised torque alone. I first calculate the roller shutter weight, identify the tube radius, check the application type, and then apply a safety margin before comparing motor ratings. This approach helps me choose a motor that can lift the curtain without excessive heat, noise, stalled movement, or premature wear.
A tubular motor converts electrical energy into rotational force inside a roller tube. The basic torque calculation is Torque = Load Force × Tube Radius. In practice, I convert the curtain mass into force, add friction and operating resistance, apply a safety factor, and then select a motor whose rated torque exceeds the calculated requirement while remaining compatible with the tube, crown, drive wheel, controls, and limit system.
A tubular motor is a compact electric drive installed inside a hollow roller tube. When activated, the motor rotates the tube, causing a roller shutter, blind, screen, or awning fabric to rise, lower, extend, or retract. Because the motor is enclosed inside the tube, the finished installation can remain compact without the external gearbox and visible drive assembly used by some other motor types.
I commonly see tubular motors used for residential roller shutters, commercial shutters, roller blinds, awnings, projection screens, zip blinds, and other shading systems. The correct motor depends on more than the curtain’s static weight. Tube diameter, curtain material, shaft geometry, operating frequency, wind exposure, installation alignment, and control requirements all affect the selection.
I begin by defining the application because the same weight can create different motor requirements in different installations. A small indoor blind may operate in a low-friction environment, while an outdoor roller shutter may experience wind pressure, guide-rail resistance, temperature changes, and more frequent movement. An awning motor may also need to handle fabric tension and a larger projection radius.
Record the following information before requesting a motor quotation:
This information allows me to compare products based on operating conditions rather than relying only on a nominal torque number.
For a roller shutter, I calculate the curtain area by multiplying width by height. I then multiply the area by the curtain’s mass per square meter and add the approximate weight of the bottom rail, locks, end slats, and other moving components.
Curtain mass = Width × Height × Material mass per square meter
For example, assume a shutter is 2.4 meters wide and 2.2 meters high. If the curtain weighs 6 kilograms per square meter, the curtain mass is:
2.4 × 2.2 × 6 = 31.68 kilograms
If the bottom rail and additional moving parts add 3.3 kilograms, the estimated moving mass becomes 34.98 kilograms. I would not treat this as the final motor load because guide friction and alignment resistance still need to be considered.
| Calculation item | Example value |
|---|---|
| Shutter width | 2.4 m |
| Shutter height | 2.2 m |
| Curtain area | 5.28 m² |
| Curtain mass | 31.68 kg |
| Bottom rail and accessories | 3.3 kg |
| Estimated moving mass | 34.98 kg |
For blinds and awnings, I use the same principle but adjust the calculation for fabric density, cassette components, roller size, spring assistance, and tension. If the supplier provides a tested load table for a particular tube and curtain profile, I compare that data with my independent calculation instead of replacing it.
Torque is determined by both force and radius. The basic relationship is:
Torque (N·m) = Force (N) × Radius (m)
To convert mass into force, I multiply the mass by gravitational acceleration:
Force (N) = Mass (kg) × 9.81
Using the 34.98-kilogram example, the force is approximately:
34.98 × 9.81 = 343.15 N
If the effective tube radius is 0.04 meters, the theoretical torque is:
343.15 × 0.04 = 13.73 N·m
This 13.73 N·m figure is the minimum theoretical torque before friction, guide resistance, wind, uneven loading, and startup conditions are included. It should not automatically be treated as the final motor rating.
I then apply a safety factor. For a controlled indoor blind with low friction, a factor between 1.2 and 1.3 may be considered during preliminary sizing. For a roller shutter with guide rails, outdoor exposure, frequent operation, or uncertain curtain resistance, I may evaluate a factor between 1.4 and 1.8, subject to supplier testing and application requirements.
With a 1.5 safety factor:
Recommended calculated torque = 13.73 × 1.5 = 20.60 N·m
I would then compare this result with available commercial ratings and normally select the next suitable rating above 20.60 N·m, provided that the motor’s duty cycle, tube compatibility, thermal limits, and installation conditions are also suitable.
Tube diameter is one of the most frequently overlooked factors in tubular motor sizing. If the same curtain weight is wound onto a larger tube, the effective lifting radius increases. Since torque equals force multiplied by radius, the required torque rises even though the curtain mass has not changed.
For example, a 300-newton load produces approximately:
| Effective radius | Theoretical torque |
|---|---|
| 0.03 m | 9.00 N·m |
| 0.04 m | 12.00 N·m |
| 0.05 m | 15.00 N·m |
This difference becomes more significant for heavy roller shutters and large commercial systems. I therefore avoid selecting a motor from curtain weight alone. I confirm the tube diameter, the winding diameter during operation, and whether the manufacturer’s torque table already accounts for the changing roll radius.
A motor can have sufficient torque and still be unsuitable if its physical dimensions do not match the roller tube. I check the motor diameter, tube internal diameter, crown size, drive wheel, adapter set, motor head, mounting bracket, and available insertion length before placing an order.
The motor must sit correctly inside the tube without excessive clearance or forced installation. The crown supports the tube’s rotating position around the motor, while the drive wheel transfers motor rotation to the tube. If either component is incorrect, the system may slip, run unevenly, produce abnormal noise, or fail to reach the intended limits.
I also confirm whether the motor series supports the tube profile being used. Common product families may include approximately 24 mm, 25 mm, 27 mm, 35 mm, and 45 mm motor diameters, but the outer motor diameter alone does not confirm compatibility. The tube’s internal geometry, adapter design, bracket position, and load rating must be checked together.
The calculated torque gives me a technical baseline, but the commercial motor rating must reflect actual operating conditions. A motor selected only slightly above the theoretical minimum may run close to its thermal limit, particularly when the shutter is large, the guides are tight, or the system cycles repeatedly.
I review the rated torque, rotational speed, voltage, current, duty cycle, operating temperature range, and overload protection. A slower motor may provide more controlled movement, while a faster motor may shorten opening time but require closer attention to limit adjustment and stopping accuracy.
A higher torque tubular motor is not automatically better. Oversizing can increase cost, affect tube fit, change operating speed, and create excessive force at the end stops if the system is poorly adjusted. I select the smallest motor that exceeds the verified requirement by an appropriate margin and meets the required duty cycle.
A tubular motor needs a reliable method to stop at the fully open and fully closed positions. Depending on the model, this may involve mechanical limit switches, electronic limits, wireless commissioning, encoder feedback, or a combination of these methods.
For a basic roller shutter, I verify that the motor supports the required limit-setting method and that the installer can access the adjustment points after the motor is installed. For smart blinds or centralized building systems, I check controller compatibility, communication method, power requirements, and whether multiple motors can be synchronized.
I also confirm whether the system requires a wall switch, remote transmitter, sensor, gateway, Matter-based control, or another building automation interface. Yozewit presents tubular motor series alongside curtain motors, control systems, sensor products, and smart-home integration options, so I would evaluate the complete control architecture rather than selecting the drive unit in isolation.
When I compare a Tubular Motor Manufacturer, I request the same technical information from each supplier. This prevents a supplier from appearing stronger simply because it reports torque, speed, noise, or capacity using a different test condition.
| Selection factor | Information to request |
|---|---|
| Torque | Rated torque and test condition |
| Load capacity | Maximum recommended curtain mass for the specified tube |
| Tube fit | Compatible tube diameter, crown, and drive wheel |
| Duty cycle | Maximum operating time and rest period |
| Protection | Overload, thermal, and electrical protection |
| Limits | Mechanical or electronic adjustment method |
| Noise | Measured value and measurement distance |
| Controls | Wired, wireless, smart-home, or centralized options |
| Testing | Sample test data, endurance results, and inspection records |
| Support | Installation instructions, drawings, and replacement parts |
Yozewit identifies Guangdong Yozewit Intelligent Technology Co., Ltd. as a Dongguan-based manufacturer focused on intelligent drive systems for indoor and outdoor sunshades. Its published product range includes tubular motors, curtain motors, control systems, sensor products, and customized OEM/ODM services. For a project purchase, I would still request the exact torque curve, tube compatibility chart, duty-cycle information, and sample validation data for the selected motor model.
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A sample test is the most practical way to confirm that the calculated motor selection works in the actual assembly. I test the motor with the intended tube, crown, drive wheel, curtain material, guide rails, bottom rail, brackets, and control accessories. Testing only the motor without the final mechanical load does not reveal alignment or winding problems.
During the test, I record:
For a multi-motor installation, I test the units together because synchronized movement may create different mechanical resistance from a single-motor test. If the motors are used outdoors, I also test the complete shutter or awning under representative wind and temperature conditions where practical.
Before approving a motor, I use this checklist:
To How To Select A Tubular Motor Suitable for Your Load Weight Requirements, I first calculate the moving load, convert mass into force, multiply by the effective tube radius, and apply a documented safety factor. I then compare the result with the nearest suitable commercial torque rating instead of choosing a motor solely by shutter weight or marketing category.
The final decision also depends on tube diameter, motor diameter, crown and drive wheel compatibility, limit-switch adjustment, duty cycle, thermal behavior, noise, controls, and sample-test results. For heavy roller shutters, large awnings, or commercial installations, I recommend validating the complete assembly before mass purchase. A supplier such as Yozewit may provide the motor, control, sensor, and OEM/ODM support needed for a broader shading system, but the selected model should still be approved against measured load data and installation-specific test results.
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