rbt said:
I am tryiing to wire up three fans.
I have a PS cable-adapter that has one male and 3 three female PS
plugs.
I would like to put in a switch.
I have another male-female PS cable bridge and a 3 pole on-off switch.
I dont think I should simply break the red with the switch
Will three 12v .18a, 12v 15a &12v 3a fans burn out the switch even if
it is stamped with [3amp 250vac] & [20amp 125 vac]?
In a PS cable-loom, is the Red cable 12volts and the Yellow cable 5
volts?.. If so I could split the fans accros the PS positives but I
still dont like the idea of the swict being wired directly into the
power loom.
Can I fit a relay? or am i worring about nothing - it would seems a
relay-switch would be safer?
Or, with the right wiring is the swith I bought already a built-in
relay switch? - it has three poles
SOME BACKGROUND
I use my machine in two modes, flat-out and idle, so Iv decided to load
it up with fans and a on-off switch running off the standard power
leads.
Ive spent some time with easy-tune5, speedfan, the 4 fan connectors on
my Gigabyte GAK8N-SLi & 4 odd-bod collection of cpu & ps fans.
Ive been trying to rig them all to go quiet but cant afford a proper
fans & solution - so just on and off would be nice.
tis
In terms of control, you should aim for a simple setup. You should have
the "base" set of fans that are always running. You don't need any
switch in that path. You can use a switch to activate your "extra"
fans.
(Not that I approve of this plan, as the best way to do it is just
set the fans up to handle the situation no matter what, as if a friend
operates your machine, they might forget to flip the switch when needed.
One poster here, had a switch for his water cooling system,
his girl friend used his computer, and forgot to switch on the
water system. Fried CPU according to him.)
First of all, be careful with the wire color, because the color standard
for disk drive connectors is different than the one for three wire
fans. So you cannot just wire "yellow to yellow", as that would be
incorrect. You can find connector pinout information, to verify what
you are about to do, so don't trust my figures below, but check
them yourself to be sure.
One way to figure out the wiring on the fan, is open your motherboard
manual. The manual will label the three fan pins, which are "RPM", "+12V",
and "Ground". The center pin (red wire) on a three pin fan header
is +12V. The black wire is ground (so at least that color is consistent).
The remaining yellow wire is the RPM signal. Fans come either with three
wires or with two wires, and a two wire fan is missing the yellow RPM signal.
A two wire fan has a red and a black wire, and red is +12V and black is
GND.
You don't need the RPM signal, and in this case, I don't see any benefit
from hooking it up.
The messy part of the job, is the connectors that are on everything.
If the fans in question, had disk drive power connectors on the end,
there would be less work to do. If the fans had the small three pin
connectors on the end, you might consider picking up some Molex
4 pin disk drive to 3 pin fan adapter cables, as a quick and easy
way of getting the wiring right.
With the fan I have sitting in front of me, this is the wiring
color scheme for the three pin small connector (the connector that
would normally go to the motherboard fan header). This is the view
looking into the end of the fan cable's three pin connector. Notice
that the pin holes are close to the place where the orienting tab
fits, when the fan connector is plugged into the motherboard.
Fan cable 3 pin connector Molex Drive Connector
+------------------------+ +12V GND GND +5V
| | Yellow Black Black Red
| Yellow Red Black | X X X X
| RPM +12V GND |
| x x x |
| ____________________ |
|_| |_|
To run the fans, all you need is to break the yellow wire on
the Molex disk drive extender cable, with your switch. Once you
modify the Molex extender cable, it should only be used for
your fan system, as switching the power off to a disk drive
would not be a smart thing to do. You cut the Yellow wire
on the Molex drive extender assembly (near the source end),
so that the switch can open or close the Yellow +12V path.
/
/
Yellow <---------* *-------->
Black <---------------------->
Black <---------------------->
Red <---------------------->
If you don't plan on getting Molex drive to three pin adapters
or the like, then the wiring straight from a Molex drive cable
to the fans would look like this. The Fan_Yellow is optional
and a computer case fan likely doesn't have an RPM. You don't have
to wire the RPM signal to anything. Make sure you insulate the end
of the Fan_Yellow wire, so it doesn't contact anything. The "X"
here means "No Connection" and "tape off the end".
/
/ X----------- Fan_Yellow (RPM)
Yellow <---------* *--------> >----------- Fan_Red (+12V)
Black <----------------------> >----------- Fan_Black (GND)
Black <---------------------->
Red <---------------------->
With more than one fan to be controlled by the switch, all the
fans run in parallel. In other words, all the Fan black wires are
joined together. All the Fan red wires are joined together. Then
connect the clump of Fan_Red wires as in the above diagram. Connect
the clump of Fan_Black wires as above.
If you have a three position rocker switch, the positions would
be ON-OFF-ON. There are a million different kinds of switches,
and it is pretty hard to guess at what you've got. If the
switch has a center row/pins and two end rows/pins, then
the switch would look like this, logically speaking. You use
a center pin, and one end pin, to get the switching action.
Rocker switch, three position Wiper closes, center to one end.
/
|\_____/| /
|_______| ON * * * ON
* * *
To use the rocker, you can use a center pin (common) and one
end pin, like this. This is what it would look like, if I
was interrupting the flow of current in the Yellow Molex wire.
/
/
ON * * * ON
| |
| |
Yellow >-----+ +----> Yellow
If you are still unsure about what you are doing, remember
that the computer works best with good cooling, and you
can always select just enough fans to keep the computer
cool at all times, and leave it that way. I don't modify
my fan cooling, and all my fans run at a fixed speed.
That way, there is no annoying ramping up and down of
fans. The computer I'm typing this on is rather loud,
but I assure you, it is always cool
And yes, I could
make a very complicated technical scheme to control the
fans, but I don't do it.
You can buy fan controllers that fit in disk drive or
floppy bays. This one, for example, takes fans from
all the way off to all the way on. Some controllers
don't have an off position. The lamps that come with
this kit are overkill. While there are many different
brands and models of these things, quite a few of
them are flaky. But there is less stripping of
wires and soldering, using a controller.
VANTEC NXP-305-SL Fan & Light Controller Panel, Silver - Retail
http://www.newegg.com/Product/CustratingReview.asp?Item=N82E16813999903
This is the controller part. Three fan control channels. One
for lights.
http://images10.newegg.com/NeweggImage/productimage/13-999-903-01.JPG
The CCFL lamps that come with this kit are overkill.
http://images10.newegg.com/NeweggImage/productimage/13-999-903-03.JPG
Paul
