Sharing fans between 2 machines.

[Lima]

The specs on my fans says 12V. Can you give me a example of 120V fan and, is it possible with my fans?

[3 of 7]

Originally Posted by Lima

The specs on my fans says 12V. Can you give me a example of 120V fan and, is it possible with my fans?

Take a look at the diagram in my last post. it makes more sense than the 120v fans.

[Lima]

o.k. The relays are pluged to the third PSU and the fans are plugged where?

[3 of 7]

The relays trigger the 3rd psu to turn on or off and the fans are plugged into the 3rd psu.

[MpG]

Originally Posted by Lima

Hey!! What about a switch that will let me shift the power source of the fans? So I can control which system powers the fans.

example: Fan to splitter > splitter to switch > one three pin connector to each motherboard. Like that, when I have the power off on the main system I can just divert power from the second machine and prevent power crossing over to the other system at the same time.

Now to find out what a switch like that would be called/or exist and where to get one.

Anyone?

This is certainly an option. What you're looking for is a Double-Pole-Double-Throw switch (aka DPDT). You can sometimes get them in automotive stores, but usually you'll need to visit a proper electronics store. You'd wire it up so that flipping the switch changes both the positive and negative leads at the same time. Here's a highly technical diagram to demonstrate.

[Lima]

And how are the fans triggered on when either one of the systems is powered up?

[3 of 7]

Originally Posted by Lima

The specs on my fans says 12V. Can you give me a example of 120V fan and, is it possible with my fans?

Just for conversation here's one of my 120v fans. This one is cast aluminum including the fan blades and draws 24w. It also sounds like an airplane.. ( It's not for the weak of heart or people who like to put their fingers in such things )

[MpG]

Originally Posted by Lima

And how are the fans triggered on when either one of the systems is powered up?

This method requires manual switching, but as soon as the PSU powers up, it will provide power for it's own wires. It's up to you to flip the switch so that the powered wires can send their power to the fan.

If you use a double-pole relay, this can be done automatically by having the relay connect the first PSU to the fan while open. Have the second PSU energize the relay, and hook up the PSU contacts to relay's closed contacts. This guarantees that the fan will always be powered, as long as at least one of the PSU's is running.

[sswilson]

Would it be worthwhile to consider using a fan controller and using the sensing relay to power it instead of the individual fans?

[Lima]

Originally Posted by MpG

This is certainly an option. What you're looking for is a Double-Pole-Double-Throw switch (aka DPDT). You can sometimes get them in automotive stores, but usually you'll need to visit a proper electronics store. You'd wire it up so that flipping the switch changes both the positive and negative leads at the same time. Here's a highly technical diagram to demonstrate.
Attachment 6627

Thanks MpG :D

Now if I could only figure out that diagram. Hmmm