How to run a 12v fan on a 48v powersupply

[HereinCS]

I'm running a 48v switching power supply. I'd like to use a 12v computer fan to keep things cool. Is it just a matter of wiring a resistor to the power lead? Can some one remind me of the calculation? Thanks.

[Dorsal]

I=E/R
http://wiki.answers.com/Q/How_do_you...12_volt_device

http://en.wikipedia.org/wiki/Voltage_divider

[vladdy]

might be easier to pick up an integrated voltage regulator, like a 7812, small size, and pop it onto a small heat sink... cheap and readily available, no calculations required...

[HereinCS]

I found a case fan that can run at 48v. Can some one take a look at my ps pictured below? It's got a couple of 48v output terminals. Is it safe to use one 48v terminal to my g540 and another to a fan?

I also found some 110v ac fans. Can I connect it to the 110v input to the power supply?

[CarveOne]

Originally Posted by HereinCS I found a case fan that can run at 48v. Can some one take a look at my ps pictured below? It's got a couple of 48v output terminals. Is it safe to use one 48v terminal to my g540 and another to a fan? I also found some 110v ac fans. Can I connect it to the 110v input to the power supply?

Using an ohmmeter, you will find that the 48v terminals are tied together in the PCB artwork under the barrier terminal connector. You can use the second terminal for a 48v fan.

I have a Keling 72vdc 20A power supply that has no 12vdc module in it, so I used two 120vac fans from Radio Shack in the enclosure, connected to the ac input fuse on the side that goes to the power supply input. The fuse holder happened to be a shorter wire run than connecting it to the power supply ac input terminals. Just be sure that removing the fuse stops the fan. Use heat shrink tubing or clear silicone sealer on the fuse holder connection to insulate it.

CarveOne

[PropNut]

I had the exact same issue....so I ordered two 120mm 48v fans from All Electronics for 10.50 (included shipping). At 1.75 each it was cheaper than purchasing a PC fan.

http://www.allelectronics.com/index...._query=48v+fan

[Phife]

buy a small 12v power adaper, you'll be better off than trying to use resistors to make 12v from 48v. you'll be adding heat that way.

[MrWild]

Originally Posted by PropNut I had the exact same issue....so I ordered two 120mm 48v fans from All Electronics for 10.50 (included shipping). At 1.75 each it was cheaper than purchasing a PC fan. http://www.allelectronics.com/index...._query=48v+fan

That's what i did also. I bought from Hosfelt Electronics though and paid a LOT more. (I think $8)

[HereinCS]

Thanks guys. I've decided to buy a 80mm 110v fan from the coolerguys.com. I have a very small enclosure and can't fit a 120mm fan. Just so I understand, can I hook up this fan to the 120v input terminal on the power supply rather than the 120v straight from the wall?

[PropNut]

Yep, it would be the same as using a multi outlet adapter on the wall.