!2v dc to 48v DC?

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Drewcoolness99

Limp Gawd
Joined
Mar 22, 2002
Messages
368
On my last trip to bg micro, I accidently picked up some 120mm fans that are meant to run off 48v dc instead of 12. How would I go about stepping up the voltage? it says 48v DC .20A.

Thx
 
Originally posted by SarverSystems
Take em back or toss em the garbage. Aint gonna happen.
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yeah it would cost you more for a transformer than to just buy more fans. i dont even know where youd get one
 
Well you can't even use a transformer to step up DC, at least not directly. It can be done, but it will take some money and some work. Best bet would be to just get some 12V fans and be done with it.
 
Originally posted by paladin0
yeah it would cost you more for a transformer than to just buy more fans. i dont even know where youd get one
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Build it yourself. I think the only place you see 48VDC used is in the telecom industry... and you won't find anything that isn't waaaay overkill and waaaay too big for just running fans.
 
why not try running them @ 12v?

if they dont draw that much you can hook up the + line to your +12 line, and then the - line to your -12v line, that will give you 24v on the fan... that might run it at a decent speed....
 
Here's an idea: You will need:
-a 2.5:1 or 3:1 transformer
-a nice bridge rectifier (out of an old PSU, maybe?)
-a couple of big capacitors

Here's a schematic:
simplePSU.bmp


Connect the left side to AC (through a relay hooked to your normal PSU if you want to be fancy). Then connect one (or two) big capacitors (as in hundreds of microfarads) across the POS and NEG terminals. Voila! you have somewhere around 40-50VDC!
 
tried running them at 12v, they won't even spin. Anyone know of any thing that plugs into the wall that converts to 48v? I know cd players use 4.5v at least mine does.
 
Most 48 volt stuff is telecommunications stuff, so most 48 volt power supplies will be big, powerful, expensive power supplies designed to run that equipment. You may be able to find a cheap one. I haven't found any yet though. In my searching I found a 12 volt to 48 volt converter that you may want to look at. They don't list the price on the website, so that right there should tell you it is pretty expensive. I can almost guarantee you that it would be more expensive than just buying new fans.

edit: found one for $29. Looks like you would need two of them for every three fans you would be running.
 
Originally posted by jpmkm
edit: found one for $29. Looks like you would need two of them for every three fans you would be running.
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More like one or two of them for every fan. You neglect to realize that fans draw a considerable amount of current when starting up, which for these fans can easily be more than .3A (which will easily strain the voltage converter and could cause them to burn out). [edit] And on top of that, your suggestion of running 3 fans off of two would be running the converters at max output, which would be unadvisable in the first place. [/edit]

IMHO it would be more worthwhile to sell them on eBay and buy new 12V fans.

-special [k]
 
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