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 even slightly above it after the 24-hour run-in. Of course, there is usually also a smaller series spread in play, so that already fits quite neatly.
In today’s DC test, we see that the fan only starts up with voltages from about 6 volts. The switch-off voltage is 3.5 volts, whereby the technically possible around 350 rpm with PWM control differs greatly from the measured 774 rpm. The fan is thus not suitable for real DC control, because you cannot regulate it down far enough with it.
The PWM-controlled start-up speed is at least 365 rpm, and the PWM-controlled fan stop is below that. The fact that our 120 model did not shut down seems to be due to the test sample, because it now worked here.
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 1292 rpm as a starting speed, and a standstill already occurs below 774 rpm. This is rather worthless as a control range and makes these fans 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) together would consume a bit over 11 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, as the power consumption increases to a whopping 3.8 watts, which is only slightly higher than the values in the spec sheet.
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