Computer Power Supply and Switch Wiring Questions

[BrianG]

Originally Posted by What's_nitro?

Where's my gold star sticker?

Good enough for you?

[What's_nitro?]

Yes, that will do.

[rawfuls]

Originally Posted by What's_nitro?

Aaaaacctualllyyy.......

It does. Either diagram would need to be hooked up exactly as pictured to work properly.

Well......
It's a dang good thing I asked then...

I was gonna just not ask and just hook it up the other way, what would go wrong if I did reverse? Sparks and sparks?

Originally Posted by BrianG

Well, 5v may work, but may not. You could temporarily wire the fan up to 5v and see if it starts reliably (may "grumble") and has the airflow you want before you make a more permanent switch setup.

I have one of the fans that I'm gonna be picking some more up later, so I'm gonna try and test that out this weekend.

If 5V doesn't do much, may just stick to 7V then..

[What's_nitro?]

I'm not sure what you mean by "hook it up the other way", but if it wasn't hooked up properly then, yes, you might see some sparks- or your computer just turns off and won't turn on again, or nothing happens at all.

Edit: There is a possibility of smoke being involved as well.....

[rawfuls]

Wired up a temporary molex connector for 5V instead of 12V, the LEDs are dim, the fan doesn't spin, turn it about 100%, then to 25% (to get the fan started), and it'll spin, however there's no noticeable airflow until around the 75% mark... (You can say it BrianG... you told me so! ).

Looks like I'll be switching between 7V and 12V... maybe.

So, in order to wire up the "temporary molex" thing, I would have the negative black wire from the fan to the red wire (5V), and the positive to the yellow wire (12V), right?
And this will just push out a constant 7V?

[BrianG]

Yeah, a constant 7v setup would be the fan - going to the 5v line, and the fan + going to the 12v line.

[What's_nitro?]

Originally Posted by rawfuls

Wired up a temporary molex connector for 5V instead of 12V, the LEDs are dim, the fan doesn't spin, turn it about 100%, then to 25% (to get the fan started), and it'll spin, however there's no noticeable airflow until around the 75% mark... (You can say it BrianG... you told me so! ).

But at least it's quiet!

[rawfuls]

So... should I be worried if I am using 7V?
I've read where 7V may be "stressful" on the PSU...

[What's_nitro?]

I'm not sure... I think BG would have mentioned it if it was a problem, though. If it's bothering you, just do the diode thing and use 7 diodes in series to drop it to 7.1 volts.

[rawfuls]

Originally Posted by What's_nitro?

I'm not sure... I think BG would have mentioned it if it was a problem, though. If it's bothering you, just do the diode thing and use 7 diodes in series to drop it to 7.1 volts.

I'm mainly worried since this PSU isn't exactly a.... "nice" PSU...
Coolmax 600W cheapie PSU, so I wouldn't know how it'd feel if I used the 7V on it.

[BrianG]

It would be stressful if you were trying to draw 10A or so, but fans use around 200mA or less each, so I wouldn't worry about it.

[rawfuls]

Originally Posted by BrianG

It would be stressful if you were trying to draw 10A or so, but fans use around 200mA or less each, so I wouldn't worry about it.

Well, I read the label, 12V... 0.40mA... So I assume that's too little to matter!

Also, I did a bit of thinking, since the "controller" varies the fan, through voltage *most likely*, on 5V, it'd probably be giving like 3V on full low..
So, on full, it ran, so HAH!

Fans: 1 - BrianG: 0.

[BrianG]

0.4A is higher than I would have expected for a typical fan, but is fine.

What do you mean by "Also, I did a bit of thinking, since the "controller" varies the fan, through voltage *most likely*, on 5V, it'd probably be giving like 3V on full low..
So, on full, it ran, so HAH!"? You have a controller that is running on 5v?

[rawfuls]

Originally Posted by BrianG

0.4A is higher than I would have expected for a typical fan, but is fine.

What do you mean by "Also, I did a bit of thinking, since the "controller" varies the fan, through voltage *most likely*, on 5V, it'd probably be giving like 3V on full low..
So, on full, it ran, so HAH!"? You have a controller that is running on 5v?

Well, I mean.
The fan is hooked to the controller, which is hooked to power.
I changed the power input to 5V (what I'm gonna end up doing..), so when I turned it to low, I would assume it changes the fan voltage down, while on full, it'll let the 5V (or whatever) go right through...

Also.. if I connect for 7V, and I'm removing the grounding wire..
Shouldn't I be... well, upset after connecting it?

I mean, I have a metal-steel controller mounted on metal-steel chassis...

[BrianG]

Ok, if you have a controller, why do you need any kind of switch?

Yes, assuming the controller is not using a switching buck/boost circuit, then the output can only be as high as the input. But, you tried running the fans from 5v before and they didn't want to start. So, if that's the case, then the controller must be outputting more than 5v.