How to reduce noise for brushed motors?

Noise reduction with brushed motors is often the most difficult challenge for design engineers when developing products, especially in equipment applications where sound is critical.

The noise problem inherent to brushed motors is the brushes. The brushes generate mechanical and electrical noise due to friction with the commutator, as well as arcing caused by the current conducted through the brushes and the commutator. A noise reduction level of 10 decibels is a remarkable achievement. The decibel scale is logarithmic, not linear. For every 3 dB reduction in sound level, the sound intensity is halved. Therefore, it is generally recommended that equipment manufacturers check the following factors at the motor angle to achieve the effect of reducing noise: study different glazing processes, inquire about custom carbon brushes, and tighten processing tolerances.

Noise reduction project For engineers working on noise reduction design, motor design is only part of the challenge. Radiated noise can be amplified by other components in the system.

So, here are some additional tips to reduce noise: first, avoid metal plates and structural parts that can resonate with the motor; second, in some cases, mounting the motor with isolators can help ; Third, align the driven parts with the motor accurately.