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 dispersion in play, so that already fits.
In today’s DC test, we see that the fan already starts up with voltages from about 3.4 volts. The cutoff voltage is 2.9 volts, whereby the technically possible around 400 rpm slightly differs from the measured 500 rpm. And it also doesn’t start up again until 600 rpm. Thus, the fan is not suitable for real DC control because you cannot regulate it down far enough.
The PWM-controlled start-up speed is 450 rpm, and the PWM-controlled fan only stops at 382 rpm. The fan fully complies with the specifications.
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 600 rpm as the starting speed, and a standstill already occurs below 500 rpm. This is rather worthless as a control range and makes these fans somehow useless as pure DC fans (see above).
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 also have to keep in mind that six fans together would only consume the 12 watts that a header can supply at full load. From this point of view, common DC control of all installed fans in a system via a single 1-A header would not be impossible if there are less than seven. But rather PWM, which regulates better.
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 just under 2 watts on the 45 mm radiator at maximum. And that only in the tips.
16 Antworten
Kommentar
Lade neue Kommentare
Urgestein
Veteran
Urgestein
Urgestein
Urgestein
Urgestein
Urgestein
Moderator
Veteran
Urgestein
Urgestein
Urgestein
Veteran
Veteran
Urgestein
Alle Kommentare lesen unter igor´sLAB Community →