Why Two 45mm Awning Motors Can Produce Different Noise Levels

A 45mm quiet awning motor is a tubular motor designed to operate below 40dB(A) under controlled load conditions while delivering 10–50N.m torque for retractable awnings, cassette awnings, pergolas, and exterior shading systems. In practice, operating noise is determined less by motor power and more by gearbox accuracy, vibration transmission, rotor balance, bearing condition, and installation compatibility. Two motors with identical torque and speed ratings can produce significantly different acoustic results after installation.

For shading system manufacturers and procurement engineers, understanding the origin of motor noise is often more important than comparing catalog specifications.

Why We Investigated This Issue

In a recent OEM project review, an awning manufacturer reported inconsistent acoustic performance across several newly installed exterior shading systems.
The motor specification was identical throughout the project:

45mm tubular motor

20N.m rated torque

17rpm operating speed

Electronic limit switch

Radio frequency (433.92MHz) control

70mm aluminum roller tube
 

Despite sharing the same specification sheet, several installations were noticeably louder during opening and closing cycles.

The question raised by the customer was straightforward:

If the motors have the same torque, speed, and control system, why do some operate at a lower noise level than others?

To identify the root cause, a comparative validation test was conducted under identical operating conditions.

All samples were evaluated using the same installation configuration to eliminate environmental variables.

Noise measurements were recorded during steady operation rather than startup or stopping sequences.
 

The test results revealed that torque output had little direct influence on operating noise.

The largest variations were associated with gearbox accuracy, vibration transfer, and rotor balance.
 

Under identical load conditions, the difference between the loudest and quietest configuration reached approximately 9dB(A).

For reference, a reduction of this magnitude is clearly perceptible in hotel, residential, and office environments.

One common assumption is that motor noise originates primarily from the stator and rotor.

The testing suggested otherwise.

In most cases, vibration generated inside the gearbox was transmitted through the drive system and amplified by the roller tube.

The vibration path followed the sequence below:
 

Gearbox
↓
Crown and Drive Adapter
↓
Aluminum Roller Tube
↓
Mounting Brackets
↓
Perceived System Noise

When a standard crown and drive adapter with excessive clearance was replaced by a matched adapter set, measured noise decreased by approximately 3dB(A) without any modification to the motor itself.

This observation explains why identical motors may perform differently when installed inside different tube profiles.
 

During disassembly and inspection, another trend became evident.

The quietest motors consistently used higher-precision planetary gear assemblies.

Minor deviations in gear tooth geometry can create:

Increased backlash

Irregular gear engagement

Harmonic vibration

Mechanical buzzing

These effects are often difficult to detect during initial commissioning but become increasingly noticeable after extended operating cycles.

The comparison below summarizes the observed differences.

For large awning projects, gearbox manufacturing quality frequently has a greater effect on acoustic performance than increasing or decreasing motor torque.

During the first few weeks after installation, many motors exhibit similar sound levels.
However, field-return analysis conducted on motors removed from service after several years revealed recurring patterns.

The most common causes of increased noise were:

Notably, these motors often remained operational.

The issue was acoustic degradation rather than electrical failure.

This finding is one reason why many commercial specifications now require endurance validation exceeding 50,000 operating cycles.

The objective is not simply service life but stable noise performance throughout that service life.
 

Mechanical noise is not generated exclusively by hardware.

Control strategy can influence how vibration is introduced into the system.

Traditional mechanical limit switch motors stop immediately upon reaching the travel limit.

Electronic limit switch systems can implement:

Soft start

Soft stop

Controlled acceleration

Controlled deceleration

These functions reduce impact forces transmitted to:

Roller tubes

Mounting brackets

Gear assemblies

Fabric tension systems

In large cassette awnings, the reduction in perceived startup noise is often more noticeable than any reduction achieved by lowering operating speed.

While both motor platforms can be configured for low-noise operation, most exterior awning systems utilize the 45mm architecture due to higher torque requirements.
 

For retractable awnings exceeding 4 meters in width, 20N.m, 30N.m, and 40N.m configurations remain the most commonly specified solutions.
 

When evaluating a Quiet Motorplatform, procurement teams typically review more than torque and pricing.

The following parameters should be verified during supplier qualification:

Measured operating noise level at 1 meter

Gearbox manufacturing process

Rotor balancing procedure

Thermal protection specification

Crown and drive adapter compatibility

Mechanical or electronic limit switch

Radio frequency (433.92MHz) compatibility

RS485 integration capability

Dry contact integration support

Endurance test records

Projects that evaluate only torque ratings often encounter acoustic complaints after installation despite meeting lifting requirements.

For OEM projects requiring specific torque ratings, control protocols, or low-noise performance targets, WJZ Motor provides engineering support, validation data, and bulk manufacturing services for 35mm and 45mm tubular motor platforms.