Server Fan Voltages

**dragon2309** · 07-03-2006, 04:29 PM

Hi, havent been here for a while. Hope you can help.

I have "aquired" an old 24-port switch, it works fine, tis just the fan has shattered its bearings and sounds like a tractor. Ive had it all open and fished about a bit, turns out the fan is 40 x 40mm and is 20mm in depth, it connects to the motherboard using a 2-pin motherboard jumper.

So i was thinking "Yay, ive got tonnes of old 40mm fans lying around, jsut shove one in there....." no, it turns out that the fan in there already is 5v, all my fans are 12v (cos there from desktops, not servers), so basically, im asking what will happen if i connect a 12v fan to a (presumably) 5v output.... I say presumably cos i dont actually know what comes out of the mobo header, the fan was 5v, but that doesnt mean the output was 5v aswell....

So yeh, can anyone tell me what would happen if i conencted a 12v fan to it.....

dragon

[-0MEGA-] · 07-03-2006, 04:33 PM

Just my opinion, but I think it will either not work, or will work but run significantly slower.

**apj101** · 07-03-2006, 04:41 PM

will run fine, but slower.

**dragon2309** · 07-03-2006, 04:47 PM

so theres not really any danger of it blowing up in my face then..?

cheers, dragon

Bootup05 · 07-03-2006, 04:50 PM

Nope

Thats why people undervolt there boards for fans to run slower, no harm can be caused!

**dragon2309** · 07-03-2006, 05:11 PM

okidoki, cheers everyone

agapetos · 07-03-2006, 05:20 PM

Why don't you just hook it up to the 12V on the PSU?
Thats usually what one would do, although you will not be able to use the BIOS
to control the fan speed and so on. It'll run at its full speed.

red+black is 12V. yellow+black is 5V.

**dragon2309** · 07-03-2006, 05:40 PM

i take it you havent actually read the post have you.....

diduknowthat · 07-03-2006, 05:47 PM

It's just like using a fan controller, which lowers the voltage for the fan to run slower.

**dragon2309** · 07-03-2006, 06:01 PM

yup, thinking about that now it does make sense..... but yeh, to the guy who said plug it into the 12v on the PSU, and also mentioned the BIOS, im working on an unmanaged swithc, not a desktop PC, there is no BIOS and there is no 12v rail on the PSU, in fact there is no PSU (at least not the conventional type your thinking of)

cheers, dragon

07-03-2006, 04:29 PM	#1 (permalink)
dragon2309 P.I Dragon Join Date: May 2005 Location: KENT, UK Age: 20 Posts: 8,494	Server Fan Voltages Hi, havent been here for a while. Hope you can help. I have "aquired" an old 24-port switch, it works fine, tis just the fan has shattered its bearings and sounds like a tractor. Ive had it all open and fished about a bit, turns out the fan is 40 x 40mm and is 20mm in depth, it connects to the motherboard using a 2-pin motherboard jumper. So i was thinking "Yay, ive got tonnes of old 40mm fans lying around, jsut shove one in there....." no, it turns out that the fan in there already is 5v, all my fans are 12v (cos there from desktops, not servers), so basically, im asking what will happen if i connect a 12v fan to a (presumably) 5v output.... I say presumably cos i dont actually know what comes out of the mobo header, the fan was 5v, but that doesnt mean the output was 5v aswell.... So yeh, can anyone tell me what would happen if i conencted a 12v fan to it..... dragon __________________ Intel Core2Duo E6600 @ 3.1Ghz - (__CPU__) eVGA 680i SLi - (__MOB__) 4Gb Corsair Dominator DDR2-800 (4x1024Mb) - (__RAM__) 250Gb Western Digital SATAII 7200rpm - (__HDD__) nVidia BFG 8800GTS OC 320Mb - (__GFX__) LG DVD+/-RW 18x DVD-RAM - (__OPT__) Triple Boot - [XP Pro] + [Vista Ultimate] + [Ubuntu 7.10] - (__OS__) [3DMARK'03 :: 25,587] --- [3DMARK'05 :: 13,989] --- [3DMARK'06 :: 8791] - (__BENCHMARKS__) dragon2309.co.uk - a little slice of geek

07-03-2006, 04:33 PM	#2 (permalink)
[-0MEGA-] VIP Member Join Date: Nov 2004 Location: Concord, NH Age: 20 Posts: 27,365	Just my opinion, but I think it will either not work, or will work but run significantly slower. __________________ Core 2 Quad Q9550 @ 4.1GHz Asus Rampage Formula X48 ATI 4870X2 2GB GDDR5 (800/1900) 4GB (2x 2GB) DDR2 960 (6-6-6-18) 750GB SATAII w/32MB Creative SB X-Fi Titanium Fatal1ty SilverStone 750W +12V@60A 3DMark06: 22605

07-03-2006, 04:41 PM	#3 (permalink)
apj101 Administrator Join Date: Apr 2005 Location: London Age: 26 Posts: 9,235	will run fine, but slower. __________________ What did one snow man say to the other? can you smell carrot? The fight is won or lost far away from witnesses - behind the lines, in the gym, and out there on the road, long before I dance under those lights. How you do anything, is how you do everything!

07-03-2006, 04:47 PM	#4 (permalink)
dragon2309 P.I Dragon Join Date: May 2005 Location: KENT, UK Age: 20 Posts: 8,494	so theres not really any danger of it blowing up in my face then..? cheers, dragon __________________ Intel Core2Duo E6600 @ 3.1Ghz - (__CPU__) eVGA 680i SLi - (__MOB__) 4Gb Corsair Dominator DDR2-800 (4x1024Mb) - (__RAM__) 250Gb Western Digital SATAII 7200rpm - (__HDD__) nVidia BFG 8800GTS OC 320Mb - (__GFX__) LG DVD+/-RW 18x DVD-RAM - (__OPT__) Triple Boot - [XP Pro] + [Vista Ultimate] + [Ubuntu 7.10] - (__OS__) [3DMARK'03 :: 25,587] --- [3DMARK'05 :: 13,989] --- [3DMARK'06 :: 8791] - (__BENCHMARKS__) dragon2309.co.uk - a little slice of geek

07-03-2006, 04:50 PM	#5 (permalink)
Bootup05 Diamond Member Join Date: Jan 2006 Location: Essex, UK Age: 17 Posts: 1,316	Nope Thats why people undervolt there boards for fans to run slower, no harm can be caused! __________________ Intel E2200 @ 3GHz Gigabyte iP31-DS3L 3GB PC-6400 C5 Sapphire 4850 @ 700/2240 WD Caviar SE 320GB - 160GB Seagate External Asus 19" Wide Acoustic Energy Aego M's Freezer Pro 7 Tagan 600W Vista Ultimate 64 SP1

07-03-2006, 05:11 PM	#6 (permalink)
dragon2309 P.I Dragon Join Date: May 2005 Location: KENT, UK Age: 20 Posts: 8,494	okidoki, cheers everyone __________________ Intel Core2Duo E6600 @ 3.1Ghz - (__CPU__) eVGA 680i SLi - (__MOB__) 4Gb Corsair Dominator DDR2-800 (4x1024Mb) - (__RAM__) 250Gb Western Digital SATAII 7200rpm - (__HDD__) nVidia BFG 8800GTS OC 320Mb - (__GFX__) LG DVD+/-RW 18x DVD-RAM - (__OPT__) Triple Boot - [XP Pro] + [Vista Ultimate] + [Ubuntu 7.10] - (__OS__) [3DMARK'03 :: 25,587] --- [3DMARK'05 :: 13,989] --- [3DMARK'06 :: 8791] - (__BENCHMARKS__) dragon2309.co.uk - a little slice of geek

07-03-2006, 05:20 PM	#7 (permalink)
agapetos Silver Member Join Date: Apr 2006 Location: AZ Age: 38 Posts: 136	Why don't you just hook it up to the 12V on the PSU? Thats usually what one would do, although you will not be able to use the BIOS to control the fan speed and so on. It'll run at its full speed. red+black is 12V. yellow+black is 5V. __________________ MoBo: GA-m59SLI-s5 Memory: Corsair TWIN2X2048-6400 2GB Kit DDR2-800 XMS2-6400 Xtreme Performance CPU: AMD Athlon 64 X2 Dual-Core Processor 4600+ Socket AM2 (89W) PSU: Thermaltake W0117RU Toughpower 750W Main HDD: Western Digital Caviar SE16 WD2500KS 250GB Serial ATA II 7200RPM Hard Drive w/16MB Buffer Graphics: MSI NX7950GX2-T2D1GE GeForce 7950 GX2 PCI Express 1GB CPU cooler is Zalman CNPS9500 AM2 CPU Cooler 19" LCD Viewsonic VX924 4ms extreme gaming

07-03-2006, 05:40 PM	#8 (permalink)
dragon2309 P.I Dragon Join Date: May 2005 Location: KENT, UK Age: 20 Posts: 8,494	i take it you havent actually read the post have you..... __________________ Intel Core2Duo E6600 @ 3.1Ghz - (__CPU__) eVGA 680i SLi - (__MOB__) 4Gb Corsair Dominator DDR2-800 (4x1024Mb) - (__RAM__) 250Gb Western Digital SATAII 7200rpm - (__HDD__) nVidia BFG 8800GTS OC 320Mb - (__GFX__) LG DVD+/-RW 18x DVD-RAM - (__OPT__) Triple Boot - [XP Pro] + [Vista Ultimate] + [Ubuntu 7.10] - (__OS__) [3DMARK'03 :: 25,587] --- [3DMARK'05 :: 13,989] --- [3DMARK'06 :: 8791] - (__BENCHMARKS__) dragon2309.co.uk - a little slice of geek

07-03-2006, 05:47 PM	#9 (permalink)
diduknowthat formerly liuliuboy Join Date: Jun 2005 Location: Massachusetts Age: 18 Posts: 6,627	It's just like using a fan controller, which lowers the voltage for the fan to run slower. __________________ Dell Latitude XT Convertible Tablet Intel Core 2 Duo U7600 1.2ghz CPU 3GB DDR2 677 Memory 120GB 1.8" PATA Hard Drive ATI Radeon Xpress 1250 Graphics 12.1" WXGA LED Touch Screen N-Trig Capacitive Touch/Active Digitizer

07-03-2006, 06:01 PM	#10 (permalink)
dragon2309 P.I Dragon Join Date: May 2005 Location: KENT, UK Age: 20 Posts: 8,494	yup, thinking about that now it does make sense..... but yeh, to the guy who said plug it into the 12v on the PSU, and also mentioned the BIOS, im working on an unmanaged swithc, not a desktop PC, there is no BIOS and there is no 12v rail on the PSU, in fact there is no PSU (at least not the conventional type your thinking of) cheers, dragon __________________ Intel Core2Duo E6600 @ 3.1Ghz - (__CPU__) eVGA 680i SLi - (__MOB__) 4Gb Corsair Dominator DDR2-800 (4x1024Mb) - (__RAM__) 250Gb Western Digital SATAII 7200rpm - (__HDD__) nVidia BFG 8800GTS OC 320Mb - (__GFX__) LG DVD+/-RW 18x DVD-RAM - (__OPT__) Triple Boot - [XP Pro] + [Vista Ultimate] + [Ubuntu 7.10] - (__OS__) [3DMARK'03 :: 25,587] --- [3DMARK'05 :: 13,989] --- [3DMARK'06 :: 8791] - (__BENCHMARKS__) dragon2309.co.uk - a little slice of geek

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