Fan connectors, motherboards, and power supplies


E

electric sheep

Hi,
I have an antec fan I got from somewhere.
It has a 3 prong connector, and a traditional 4 socket connector (like what
connects to hard drives).
It works with the 4-socket, but not when the 3-prong is plugged into the
mobo's "power fan" connector.

However, I noticed when both are plugged in the BIOS can detect the RPM's on
the fan.
So my question is, is that 3-prong connector just for relaying "information"
to the mobo basically ?
And not for actually supplying power ?
I know I've seen a 3-prong to 4-socket adapter before, so I'm assuming that
it should be able to supply power.

I would think either the mobo or the fac were busted, but then how could the
mobo know it was there and what the RPM's are ?
I couldnt find anything in the BIOS to "enable the fan".

Also, my antec power supply has an identical 3-prong deal.
Is this for relaying info on the state of the power supply fan ?
Maybe some 3-prongs are set up to accept power and others are set up for
"informational" purposes ?
 
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R

Richard Dower

electric sheep said:
Hi,
I have an antec fan I got from somewhere.
It has a 3 prong connector, and a traditional 4 socket connector (like what
connects to hard drives).
It works with the 4-socket, but not when the 3-prong is plugged into the
mobo's "power fan" connector.
Not sure i understand this fully...you have two connectors on this fan?...or
does the fan have a 3 pin connector with red, black, yellow wires?

The yellow wire is for fan RPM detection in BIOS, the other two wires supply
power.

If it does have two connectors then just plug one into your mobo for fan RPM
detection and the other 4 pin to your power supply.

However, I noticed when both are plugged in the BIOS can detect the RPM's on
the fan.
So my question is, is that 3-prong connector just for relaying "information"
to the mobo basically ?

Yes...if that connector only has one wire, if it's just a yellow wire then
this connector is just designed to be used for fan RPM detection only...it's
not to supply power to the fan or using the mobo to power the fan.

And not for actually supplying power ?
I know I've seen a 3-prong to 4-socket adapter before, so I'm assuming that
it should be able to supply power.
It can and it does, that fan might have a high power usage, maybe a high RPM
fan that eats alot of juice...thus powering it from the mobo might damage
the mobo and the fan.

So you have a 4 pin connector for connecting direct to your power supply,
and i am betting this 4 pin only has two wires connected to it, red and
black.

Then a separte connector that's a smaller 3 pin with just one wire,
yellow...thus you're getting the best of both worlds.
I would think either the mobo or the fac were busted, but then how could the
mobo know it was there and what the RPM's are ?
I couldnt find anything in the BIOS to "enable the fan".
You don't enable anything, all you do is enable the mobo to detect fan RPM.
Also, my antec power supply has an identical 3-prong deal.
Is this for relaying info on the state of the power supply fan ?
Maybe some 3-prongs are set up to accept power and others are set up for
"informational" purposes ?

Good god man, RTFM!!!!....you connect that 3 pin Antec connector to your
mobo...it's just for fan RPM detection in BIOS.

YES...look at the wires, if it's only got one wire attached, a yellow one,
it's only intended for fan RPM detection.
 
E

electric sheep

Richard Dower said:
Not sure i understand this fully...you have two connectors on this fan?...or
does the fan have a 3 pin connector with red, black, yellow wires?

The yellow wire is for fan RPM detection in BIOS, the other two wires supply
power.
yeah, it has a 3-pin connector, but i think it only has 2 wires ... both the
same color.
maybe it is missing the power wires is the deal.
the other connector is just like a hard drives.

maybe for some reason they prefer you to get juice from the power supply,
but give you the other connector so the mobo can monitor it ?
that's probably all it is.

How about the power supply 3-pin connector ?
Is that so you can monitor the power supplies fan I guess ?
 
R

Richard Dower

yeah, it has a 3-pin connector, but i think it only has 2 wires ... both the
same color.
maybe it is missing the power wires is the deal.
the other connector is just like a hard drives.
What colors?...if it's red and black then this is for power only, not fan
RPM.

It could be faulty or damaged, what not simply buy some nice new fans from
Vantec?

maybe for some reason they prefer you to get juice from the power supply,
but give you the other connector so the mobo can monitor it ?
that's probably all it is.

They do...if the fan is high RPM and eats alot of juice you must connect it
directly to the power supply.

http://vantecusa.com/tornado.html

They then have a separte 3 pin connector with just a yellow wire that allows
you to monitor fan RPM.

How about the power supply 3-pin connector ?
Is that so you can monitor the power supplies fan I guess ?
Yes...this is mine:

http://www.antec-inc.com/pro_details_powerSupply.php?ProdID=20481

I connect the 3 pin direct to the mobo for fan RPM detection in BIOS.
 
D

Dan Spears

The new vantec 80 mm fans have a three pin connect to connect to the
motherboard that reads the RPM's only. No power on the three pin connector.
The four pin connect is where the fan gets it's power. You can still buy the
vantec three pin only connector but they are very rare since they have been
discontinued.
 
R

Richard Dower

Dan Spears said:
The new vantec 80 mm fans have a three pin connect to connect to the
motherboard that reads the RPM's only. No power on the three pin connector.
The four pin connect is where the fan gets it's power. You can still buy the
vantec three pin only connector but they are very rare since they have been
discontinued.
I have them, i have seven 80mm Vantec Stealth fans with the 3 pin connector,
they are all hooked to the Digital Doc 5 for fan RPM monitoring and power.
It keeps everything nice and tidy.
 
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R

R_Supp

Richard Dower said:
I have them, i have seven 80mm Vantec Stealth fans with the 3 pin connector,
they are all hooked to the Digital Doc 5 for fan RPM monitoring and power.
It keeps everything nice and tidy.
Your fan is rated at 12.5 watt and your mobo fan headers are rated at just a
tad over 8 watt so if you could connect the fan to the mobo you would fry
the header. Connecting the fan to the PSU and the tacho wire to the header
is the correct way to use this fan.
Always check fan specs before blindly connecting them to the mobo.
 
R

Robert Hancock

High-speed or high-airflow fans typically draw a lot of power, more in some
cases than the motherboard fan connectors can supply without burning the
traces on the board. In this case, they use a power supply connector for the
power, and the 3-pin connector is for RPM monitoring only.
 
S

Stephan Grossklass

Remains to be said that if you're using one or even more fans drawing
12.5 watts in an ordinary home PC you're most likely doing something
wrong in terms of ventilation, not to mention deafness before and/or or
after using those. ;) Two 26 cfm / 45m^3/h 80x80 fans (<2 watts and ~20
dB(A) each) at the back of the case shouldn't have much trouble even
with the heat generated by a P4 3.2 GHz and a Radeon 9800 Pro. Just
looking at the specs for the Vantec Tornado that indeed draws 12.5 watts
- a 92x92x38 fan rotating at 4800 rpm with an airflow of 119 cfm (!!!)
and a noise level of 56.4 dB(A) (ouch!!!1). Might make a nice motor for
a model jet or something, but apart from that it's not something you'd
want to have near you when powered on, let alone in a PC!

Stephan
 
R

Richard Dower

Stephan Grossklass said:
Remains to be said that if you're using one or even more fans drawing
12.5 watts in an ordinary home PC you're most likely doing something
wrong in terms of ventilation, not to mention deafness before and/or or
after using those. ;) Two 26 cfm / 45m^3/h 80x80 fans (<2 watts and ~20
dB(A) each) at the back of the case shouldn't have much trouble even
with the heat generated by a P4 3.2 GHz and a Radeon 9800 Pro. Just
looking at the specs for the Vantec Tornado that indeed draws 12.5 watts
- a 92x92x38 fan rotating at 4800 rpm with an airflow of 119 cfm (!!!)
and a noise level of 56.4 dB(A) (ouch!!!1). Might make a nice motor for
a model jet or something, but apart from that it's not something you'd
want to have near you when powered on, let alone in a PC!
I've got 14 fans in my case, yes it's like being at an airport, with most of
the noise generated by the Volcano 7+....but i'm used to the noise now.
 
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R

r

I've got 14 fans in my case, yes it's like being at an airport, with most of
the noise generated by the Volcano 7+....but i'm used to the noise now.

WHAT? I CAN'T HEAR YOU!!

;-)
 
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