I have a project involving a 200mm 12VDC PC cooling fan (FS-200RB) that will be used for cooling me - not a computer.
The fan is labeled:
12V DC / 0.42A / 5.04W
With a source of 12V, it is not moving enough air for my taste.
I don't need the fan to last a long time, it will only need maybe 20hrs of use for my project, but I'd of course prefer to avoid destroying it.
With 12V applied, I measured the current in-line to only be about 0.13A. And if I hold the blades to stall it, the current only rises to 0.18A.
With 15V applied, and the current was 0.17A full speed, 0.22A stalled.
I want to overvolt this fan even more, but I'm not sure where to draw the line. I could continue raising the voltage past 15V, but I don't know how quickly it can be expected to fail.
I'm also not sure why the current would be so much lower than the 0.42A rating. Is this common for DC motors? Is 0.42A only for the instant it starts up? Stalling it doesn't even reach near that much current. This makes me feel like the fan is not reaching its normal potential, let alone an "unsafe" potential.
Why would the fan be using such little current and how can I theoretically/numerically determine an over-voltage limit?