Start-up and shut-down voltage
This chapter should be read with caution and attention as long as the fans are not purely analog, i.e. DC-controlled with 3-pin connector. The PWM control electronics almost always stand in the way of clean voltage regulation and it is also therefore not advisable to regulate PWM fans via voltage. Nevertheless, we also performed this measurement for all models, regardless of whether they are DC or PWM fans, because even strange results say a lot about the control electronics and the use as a DC-controlled fan.
First, however, we check the maximum speed at 100% PWM to be on the safe side and compare it with the data sheet. The fan manages the specified data and is only slightly below it after the 24-hour run-in. Of course, there is usually also a smaller series dispersion in play, so that already fits.
In today’s DC test, we see that the fan only starts up with voltages from about 5.3 volts. The cutoff voltage is 3.5 volts, whereby the technically possible around 600 rpm slightly differs from the measured 632 rpm. This means that the fan is not suitable for real DC control, because you cannot regulate it down far enough.
The PWM-controlled start-up speed is at least 600 rpm, so there is no PWM-controlled fan stop. Too bad, but the fan is actually completely inaudible.
Start-up and shut-down behavior
The following measurement curves once again illustrate the very different behavior. Let’s look at DC control first. Here, the new fan requires a very high 1385 rpm as a starting speed, and a standstill already occurs below 587 rpm. This is rather worthless as a control range and makes these fans kind of useless as pure DC fans.
With the PWM protocol, we can also see very well the progression up to the minimum speed, which then leads to the desired standstill.
Power consumption
This value of open operation as a case fan is pleasantly low, especially at low speeds. However, you should also keep in mind that 3 fans (without RGB) would consume around 12 watts at full load. From this point of view, a common DC control of all installed fans of a system via a single 1-A header would be impossible anyway, if there are more than three. So rather PWM.
However, power consumption is not the same as power consumption, because it fluctuates quite a bit between radiator operation and free installation as case fan! This graph is also new and should help in assessing the system load, because the power consumption increases to a whopping 4.4 watts, which is more than 10% higher than the values in the data sheet!
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