AC or DC fans?

[blowfly]

Does anyone have a preference for fans? Its seems like AC is easier than DC because you don't have to supply current through an AC to DC converter, but DC seems like it could be safer for wiring in a projector. Thoughts?

Mike

[kiyoukan]

i use pc dc fans as you most of the time already have enough dc current.
I run most mine on 5V as they are way to loud at 12v.
then again i have a micro 100w PC PSU for running my tecs and fans as well as a few controllers.
http://www.impactcomputers.com/1728p.html#
There kinda nice.

[dnar]

DC fans are safer as you say, and you don't have the hassle of all the mains wiring.

I find DC fans cheaper than AC also.

Another good trick for 12V fans is to run them from 7V to reduce noise. Wire the + to +12 and - to +5 and you have 7V.

[-bart-]

DC fans are safer as you say, and you don't have the hassle of all the mains wiring.

I find DC fans cheaper than AC also.

Another good trick for 12V fans is to run them from 7V to reduce noise. Wire the + to +12 and - to +5 and you have 7V.

Not a good idea ! I learnt about that the hard way.
That way the 12v supply sources the current, while the 5v supply sinks the current.
Most supplies DONT like sinking current ! If the load on the 5v supply is sufficient you might not notice that.

If you remove the 5v load or if you have a short in your fans the entire 5V rail will lift to 12V.
NOT GOOD!

[kiyoukan]

well if you are using a pc psu you should have a hard load built in (10W resistor) to make sure that everything is always regulated.

[-bart-]

If you want to use a resistor, put it in series with the fan.

Using a PC psu with mods in a projector is geekyamateurmakeshift-ism. NOFI

/on topic

I suggest DC fans:
Better speed regulation
Cheaper and safer
Wider choice small diameters

[kiyoukan]

well when i use a PC based tec controller and fan controller and a few other modded pc hardware i kinda like to have a psu in a small form factor to power it all. instead of having another set of psus with 12 and 5V as i have my lasers on their own lambada din psu.

[Xytrell]

har har

[JohnYayas]

I went with AC fans because I didn't feel like burdening my power supplies or putting motor noise on the DC lines. Maybe my concerns are unfounded but I am have been happy with my decision.

[steve-o]

I use AC fans for simplicity, just route wiring far from any sensitive signal lines and all is good and well :]