using pc psu for 12vand 5v fan supply. What is the neg 12v supply about?

foza

Member
Hi all


I think this should be an easy question for some


Im going to be using a 450w psu to power 2x12v .3a pc fans and another 2x5v smaller fans.

I have experience with electrical theory but still seem to get confused, especially with dc cause most of my work relates to ac currrents, and my training was years ago lol.

The pc psu supplies 3v, 5v, 12v, in both negative and positive. the positive supplies have more amperage, the negative supplies have less amperage.

Can i run my 12v and 5v fans off the negative 12v and negative 5v supply? im thinking of doing this if possible because the neg 12v only gives .8 amps, which is much closer to the combined fan draw of .6 amps. (the pos 12v gives like 30amps).

would there be a problem running the 12v fans (.6 amp) off the pos 12v supply with a 30amp rating? (from my knowledge i think that will be ok cause the fans will only draw amperage up to their specified ratings, up to the point they are doing their maximum work).

also, i want to save as much power as possible. would running the psu rated at 450w waste alot of power considering i only need around 20w with the four fans?

Would it be a better option (in relation to power use) to simply find old 12v and 5v transformers from phone and laptop chargers?

thanks guys!@!! i dont wanna burn my house down unless its on purpose, using fuel and a lighter lol

peeeaace

also, if i ran 2 fans from the 24v dc with in a series circuit, would that mean each fan draws 12v each? cant remember the theory dammit lol.

do u reckon i could remove the fan from the actual psu casing and use it elsewhere while still using the defaned(lol) psu to supply 12v power to the other couple of fans?

just wondering cause i can use the spare fans, and really the psu will only be drawing .6 amp for 2 pc fans so id imagine there wouldnt be the need for very much cooling inside the psu
Is a psu just normal transformer inside its casing?

please help :)


 

imchucky666

Well-Known Member
Sounds like you are asking for trouble.
For one thing, there should be no question about amperage consumed and amperage provided.
My suggestion would be to just get regular transformers and be done with it.
You will waste more time when you need to keep re-reading answers given after you confuse yourself.
 

foza

Member
yea good point dude. over thinking can be good sometimes, but yea it often just leads to confusion. there's no real need to install the psu in a cab as small as mine anyway. a psu would use up valuable space too. i just have to keep an eye out for the right transfomers (wanna avoid buying on, they r pretty pricey at my local stores, but they are hard to find too).
 
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