I have a cooling fan, it works fine on my server rack, but i'm confused. Yesterday I saw sparks from it. I pulled it apart and there is a cooling fan with 3 wires. Red for positive, Black for negative, and a green wire. The red and black are connected so the fan works, but the green doesn't seem to do anything. Any ideas what this could be? Can i cut it?
Sounds to me like the green is a ground wire. I think you could connect it to the case, or the server rack, and the sparking would probably stop. I'm sure someone will correct me if I'm wrong.
But if the black wire is the negative, wouldn't that be the ground wire? Maybe it's some sort of monitoring or control wire?
Again, I could be wrong, but my understanding of wiring (mainly from replacing ceiling fixtures) is that there is a "hot" (positive) wire, another main power wire (usually the black), and a ground. I don't know why it is that way, but that seems to be standard.