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Electrical question

Elite

Elite

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Hi guys,
Need some help with electrical before I kill myself or burn down the house :D...

I bought couple computer fans for my light fixture. It's 12VDC, .16A. I just need a power coverter adapter that has 12VDC output and the amp is .16Ax2 or higher right??? How do hook it up? There are three wires (red, yellow and green). Which one is which?? Thanks!!
 
First question: Yes. Your wall wart will pull however much current that will flow for whatever voltage is applied, most likely the plug is made for something with a lot more resistive of a load, as a result you'll have a higher voltage, but no biggy the fans just spin faster.

As to how your hook it up... low voltage dc like this is easy to play around with, strip the wires, plug the thing in, and hold one side to one wire, then with the other just touch each wire in turn to see which way the fan spins, can't help you on color, but if you have it hooked backwards the fan will spin backwards (you don't want that)... worst case scenario you touched the ground, in which the fan won't spin at all, however no harm if you touch the wrong wires. Polarity does matter though (that whole spin direction thing).. so just play around with it until you find the right direction.
 
All the PC fans I've worked on only use 2 wires but the plug on the end is entended for passing through to other computer parts. A lot of them are not polarity sensitive either so they will spin the same direction either way you connect the wires. hth
 
Thanks Mike, I don't want the fan to spin faster than it supposed to. Faster = noiser ;D .

So if I get one that is 1Amp the fan will spin much faster than the .5Amp one right?? The fan is only .16A. I'm not sure if I can get something that low.

Thanks Levi.. That's take care the wiring issue :D ..
 
Voltage should ultimately dictate as fast is it spins, the total current that's drawn is dictated by the voltage and resistance of the unit (fan)... want to slow it down? Put a resistor in line to drop the voltage.

Will a 1amp fan spin faster? Not necessarily, it could simply have more resistance which causes more of a current pull.
 
yeah, you want to hook them up... parallel and you can get the same voltage to both. Or you could hook them up in series halve the voltage, and they'll run slower if they're too noisy.
 
Well I couldn't find a 12VDC out of 10 plus adapter that I have. Hook up a 9VDC and it works fine. It push enough airs so I don't think I need a 12VDC one.

How do you hook them up as parallel?

Edit: found it.. so ignore the last question.. Thanks Mike!!!
 
Parallel is the "positive of the plug goes to both "positive" ends of each fan, so all the positives are essentially wired together (even if you put an intermediate wire to separate them), ditto for the negative ends.

parallelcircuit.jpg


As opposed to a connection in series, where they're wired one after another.

seriescircuit.jpg


Edit: whoops was answering before I saw your edit! Oh well, electronics is good for everyone :D
 
Hey Phong, if you look for a fan speed adjuster, they have them for PC computers. You just hook it up in-line with the fans, and there's a little knob to adjust the voltage (and speed) of the fans.
 
I know, but the benefit for me was I could turn them down when they were too loud (movie or something going on in the same room as the tank).
 
I don't think you can wire them in parallel can you? I'm saying that because your average PC fan already has the wires soldered to a small board on the fan housing... unless you really want to solder on he board?
 
[quote author=phishphood link=topic=5377.msg66749#msg66749 date=1228203932]
I know, but the benefit for me was I could turn them down when they were too loud (movie or something going on in the same room as the tank).
[/quote]
IC what you saying.. I don't really have a problem with that. If needed, I turn off the whole thing :D ..

[quote author=LeviT link=topic=5377.msg66765#msg66765 date=1228226811]
I don't think you can wire them in parallel can you? I'm saying that because your average PC fan already has the wires soldered to a small board on the fan housing... unless you really want to solder on he board?
[/quote]
I think you can.. The wires on the fan I bought have a -/+ wire. If you don't connect it right, it won't spin. Weird :- ... I will figure out how to cut a hole in the fixture and install the fans today. I will let you know for sure.
 
[quote author=LeviT link=topic=5377.msg66765#msg66765 date=1228226811]
I don't think you can wire them in parallel can you? I'm saying that because your average PC fan already has the wires soldered to a small board on the fan housing... unless you really want to solder on he board?
[/quote]
Sure you can, fans are normally hooked up in parallel inside the computer case when hooked via the adapter, if they weren't every time you added a fan all of them would slow down.
 
[quote author=sfsuphysics link=topic=5377.msg66769#msg66769 date=1228229437]
Sure you can, fans are normally hooked up in parallel inside the computer case when hooked via the adapter, if they weren't every time you added a fan all of them would slow down.[/quote]
My bad, you are right.
 
Phong, I just cut a hole in the wood w/ a hole saw that's about the same diameter as the fan. Then the fan goes on the inside and is screwed into the wood.
 
The fan will be on top. The sides do have metal sheet cover too.. If it's wood, it would be too easy. It's suck when you don't have the right tool. ::)
 
Phong...if you are going to wire the fans in parallel, you should make sure that the wall wart should be able to supply the current demand for all of them. Fan wires in series will draws the same amount of current but if one goes, so will the rest. Fans that are wired in parallel draws the amount of current independenly but the one with the least resistive load will draw the most. However, the bad one usually won't effect the other one if fails as an open circuit. If any of them fails as a shorts (less likely) then it can also kill your power supply but your other fans should be okay. Also, if you're going to go the parallel route, I would total up all the amperage of each fan and then select the appropriate adapter for your circuit...else you'll can shorten its life sooner. Hope I didn't confuse you, or myself.
 
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