I bought two fans and an adapter from lumenlab, I don't know how to wire them because on the fan there are three wires (Yellow, Red and Black) and the Adapter is plugin kind with two wires. Do I need to cut the wire ends from both fan and adapter? If so which wire goes where? Please help. See pics below:

You have to cut off the ends of the AC adpater. There should be 2 wires, one for 12volt and one for ground. If you have a multimeter you can check to see which one is which. If the reading shows -12volts then reverse the connections. If it says +12 or just 12 volts then the wire on the adapter that is connected to the red on the multimeter is +12 and the other is ground.

You will also need to cut off the ends of the fans. You only need the red and the black. The yellow is for detecting the speed, which is used more in computers. Now just connect the red wire to the 12 volt of the adapter and the black to the ground. You can twist the connections together and plug the adapter into the wall to make sure everything is working. However the projector will have other components that will need those connections(ie, LCD, ballast, fans) which you'll need a terminal strip for.

That should get you started. Just look over the diagrams and look through the electrical section of your local hardware store to find out what parts you need. Just ask if you have other questions.

If you dont have a multimeter, you can also make an educated guess...looking at the wire from the adapter, one of them is 'striped'...this usually indicates that is the negative lead (i've never seen it as the positive, but never say never) In your picture of the adapter, the one closest to the bottom of the pic appears to be the negative, and should therefore be hooked up to the black wire on the fan.

Also, it wont damage anything if you get it backwards...your fan will simply spin the wrong direction and probably wont have as much air flowing through it.

erg! I found out the hard way that, No, they won't spin backwards. The fan will simply sit there and do nothing. At least, that's what happened to me on 2 separate fans.

Also, I hooked a multimeter (voltmeter) to the ac adapter I have. With the positive (red) hooked to the wire (or lead) with the white stripe, I got a read out of about positive 19 V. So the white stripe on my adapter is positive lead..., but I don't understand - Why is it reading higher than the setting of 12 V ? Maybe b/c it's not plugged into anything so - When I connected it to my fans, I got readings of about 13 V ...still a little too high?

Those readings are about right. The output of most of these small "wall wart" type power supplies is not regulated. In my experience, with no load, the voltage will be about 18 or 19 volts. The 13 volt reading under load should be ok.

The above is the same experience that I've had. I hooked my fans up backward and they did not spin at all. I think it may be AC motors that reverse direction when hooked up backward.

Also, it's always been my experience that the different wire is the possitive. By "different" I mean whatever wire has something added to it to make it different than the other one. The addition could be as little as some writing, a line, some dots, a stamp mark of some kind, etc.

Also, on those types of adapters the wire that leads to the center of the plug is almost always the positive (I have not noticed any that don't conform to this rule). If you cut apart the plug it should be very aparrent which wire leads to the center and which leads to the outside of the plug. If you can't manage to cut it apart, you could use a battery and a small lightbulb to test which wire connects to each part of the plug.

Don't want to take my word for it? Just check out the diagram on any wall wart you have laying around...
Here is a picture from this website: Access Communications Pty Ltd...

There should be a similar diagram on all wall warts. Look at the circle and the dot. The dot (symbolizing the center of the plug) has a + attached to it meaning that it's the positive. The circle (symbolizing the outside of the plug) has a - attached to it meaning that it's the negative.

Hope this helps someone out there...!

AC motors turn one direction; DC motors generally reverse direction when the current is reversed. Most computer fans are DC and will reverse direction. If it's a biscuit fan, then all you have to do is flip the fan over rather than rewire.