Endorfy Fluctus 140 PWM ARGB works, looks come second

Mounting and vibration measurement

The first Fluctus 120 PWM fans marked a great qualitative progress in SilentiumPC production (now Endorfy). Nevertheless, they had their flaws, which the developers are gradually eliminating and, based on the measurement results, the newer 140 mm Fluctus can be said to be a clear improvement. The Fluctus 140 PWM ARGB stands out nicely from other fans in its price category.

Mounting and vibration measurement

Naturally, each tested fan must first be properly mounted. With all that we want to measure, and with the kind of precision that is required for relevant measurements, even the smallest details matter. The whole mounting system is quite complex and we are happy to have fine-tuned it to maximum satisfaction. Even if it meant hundreds of hours of tinkering. What’s so complicated about it? There’s more.

The fans are installed to the multi-purpose bracket. The substrate is a 2 mm thick metal plate to which the fan is attached, or the fan is attached together with an obstacle (e.g. a filter, hexagonal grille or liquid cooler radiator).

Bracket for installing the fan and vibrometer sensor

For correct and always equal pressure, the fans are always tightened with the same force with a torque screwdriver. If this were not the case, joints and clearances in the assembly could arise, in short, uneven conditions with undesirable distortion. For example, also for vibration measurement. On top of the fan mount there is also a bracket for the three-axis vibrometer sensor. The latter is magnetically attached via a steel insert, on which the sensor exerts a force of one kilogram and, thanks to the stop, is also always in the same place and in the same contact with the rest of the structure. These are the basics in terms of repeatability of measurements.

In order to capture the intensity at the highest possible resolution, the tray of the holder cannot be too heavy and at the same time it must be strong enough not to twist. This would again cause various distortions. Therefore, we used a hard (H19) aluminium (AL99.5) plate for the construction of the holder, whose weight is just enough so that free movement is not significantly restricted.

To achieve the finest possible resolution for vibration measurement, soft rubber inserts are provided in the mounting holes through which the bracket is installed to the tunnel. And just behind these inserts are silent blocks with a very low hardness of 30 Shore. These are also used so that the vibrations of the fans don’t spread to the tunnel skeleton. If this were to happen, then for fans with more intense vibrations, this secondary noise component, which is not related to the aerodynamic sound of the fan, would also be reflected in the noise measurement results.

Sensitive mounting mechanism allows high-resolution vibration measurement while preventing vibrations from traversing to the wind tunnel skeleton

This is where it is good to have ideal conditions, even though they are unattainable in practice, because fan vibrations will always be transmitted to the case skeleton to some degree. But each cabinet will react differently to them, or rather the final noise level will depend on a number of factors, starting with the materials used. Therefore, it is a good idea to filter out this extra noise component in tests and in practice take into account the measured vibration intensities. The higher these vibrations are, the higher the noise addition has to be taken into account.

The silent blocks are naturally formatted to offset the bracket a bit from the rest of the tunnel, otherwise they wouldn’t make sense. This creates a gap that is sealed across the entire surface with a soft foam seal with closed cell structure (i.e., it’s airtight).

To prevent vibrations from passing through to the wind tunnel structure, there is a small gap between the fan bracket and the leading edge of the tunnel, which is sealed by a soft foam collar

To properly center the fan rotor in relation to the other elements, the bracket includes a protruding frame that follows the inner contour of the seal. And to make matters even more complicated, the frame with the tested fan is pressed against this seal by a small force of compression springs, which in turn is set with the highest possible resolution for vibration measurement in mind and at the same time so that sufficient pressure is generated to maintain a flawless seal.

Vibration is measured with a Landtek VM-6380 vibration meter. It records the vibration speed (in mm) per second in all axes (X, Y, Z). For quick orientation, we calculate a 3D vector from the measured values and graph the “total” vibration intensity. But you can also find your results if you are only interested in a specific axis.

The most complicated part of the tunnel is behind us, and we’ll move on in the next chapter. But we will still stay at the beginning of the tunnel, we will just turn to the peripheries on the sides.


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Comments (3) Add comment

  1. I have several general questions.

    I see how the exhaust airflow pattern is often commended on. By how much does airflow pattern affect cooling performance? For example, assuming two fans have identical airflow rate on a thin radiator. One fan has cylindrical exhaust while the other has conical exhaust. Alternatively, one has a larger fan hub and the other has a smaller one. Or just different blade design in general. Does cooling performance differ, and if so, by how much? How about for case fans? How about on the intake side, does airflow pattern differ there?

    The wind tunnel is made free of dust before testing. By how much does dust settled on the wind tunnel/fan blades etc affect airflow and noise? Would a thin layer significantly affect the results?

    1. Great questions. We have had the ones from the first paragraph jotted down for a while and we will deal with them later in specialized tests. We just have to work our way through the other topics. 🙂

      As for the effect of fan “dirtiness” on air flow, I wonder how this could be tested. Of course, we keep the wind tunnel as clean as possible (it is even stored in a vacuum chamber) and I don’t think it is a good idea to risk changing the friction or reducing the anemometer speed by some sediments from the tested fan. But we’ll figure something out. For this purpose we could use some of the prototype tunnels that preceded the final one we are using. They have some imperfections, but they should be suitable for this purpose.

  2. I’m in love with these deeply scientific reviews. No other reviewer, ever, anywhere, went to such lengths and details in their reviews, especially about pc fans. Because of them I’m getting now 2x Endrofy Fluctus 140 argb for a top exhaust on case with grill+ dust filter. Having read all other reviews, I do prefer them over Pure Wings 3, they seem to be more efficient and more quiet at similar settings.
    Thank you!

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