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Smooth Commutation Drive

Next to aerodynamic noise and bearing related noises, the so called "commutation noise" or "switching noise" can play a major role in the noise emission of axial fans with brushless DC motors. At each transition from one stator coil to another, the rotor receives a sudden torque pulse when the next coil switches on. Each of these torque pulses causes a minute deformation of the whole fan structure. Depending on rpm, torque and the material of the fan, this can result in noticeable noises.

Noctua's Smooth Commutation Drive system provides more continuous switching in order to achieve a smoother transition between the stator coils and thereby significantly contributes to the fan's overall quietness. The second generation of this technology (SCD2) further improves running smoothness and reduces minute noises in close proximity to the motor.

28.08.2014 - NH-D15
Test verdict: "Mit dem NH-D15 ist Noctua wirklich ein Meisterwerk gelungen!" (Jens Pressel,

27.08.2014 - NF-S12A FLX
Test verdict: "Bref, une référence absolue dont vous ne pouvez être déçue et que je vous recommande chaudement." (Cadoret Gwenael,

25.08.2014 - NF-S12B redux-1200 PWM
Test verdict: "The Redux fans, are by a significant margin, the best value-for-money cooling product I’ve used and a worthwhile investment." (John Williamson,

23.08.2014 - NA-SRC7
Test verdict: "En definitiva, el set de adaptadores NA-SRC7 es un excelente complemento de la serie redux, que también puede usarse conjuntamente con otros muchos ventiladores de 3 y 4 pines y que desde RealHardTechX animamos a utilizar a los fanáticos del silencio, que nos consta que sois muchos. Recomendado." ((José Romero,