Power supply question

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Vic Baron

I have an 850W PS. Thinking of this like a typical house circuit with a 100
amp main and 30 amp circuits where you can overload a circuit but not blow
the main...... would there be any problem it attaching 10 120mm fans to one
of the connectors as opposed to spreading them out over several?

Trying to keep the case wiring minimal and if I can connect all the fans on
one power cable it would help.

Thanx
--
There are 10 kinds of people - those who understand binary and those who
don't
 
>> would there be any problem it attaching 10 120mm fans to one
of the connectors as opposed to spreading them out over several? <<

First, you have to take full responsibility for doing anything like
this, but...

If you open most power supplies, you will find that the color coded
multiple wire bundles are all soldered to the same spot within the case,
so the tech answer to your question is yes as long as the single wire
coming out of the power supply is large enough to safely carry the
amount of current totaled up by the ten fans.

Personally, I wouldn't do it with all ten fans... but would at least
create two for five fans.

Look on the fans for the specs... either amps (milliamps) or watts, and
post that here if you can't determine the total amps that ten would
pull... also post the voltage and wire "color" as that will determine if
the fans are 12v or 5v ...which directly relates to the amps...and
directly relates to the recommended wire size.

Beverly Howard [MS MVP-Mobile Devices]
 
Thanx, Beverly - you've answered my question. Sort of what I thought but
don't have a spare PS to dismantle <g>. Not a problem to spread the load and
actually it's only 4 120mm fans, 2 90mm fans and a water pump. Everything
else is SATA and the PCIx video card which have their own connectors.

Thanx again,

Vic


"Beverly Howard [Ms-MVP/MobileDev]" <BevNoSpamBevHoward.com> wrote in
message news:Ow8gC%23M5HHA.4164@TK2MSFTNGP04.phx.gbl...
> >> would there be any problem it attaching 10 120mm fans to one

> of the connectors as opposed to spreading them out over several? <<
>
> First, you have to take full responsibility for doing anything like this,
> but...
>
> If you open most power supplies, you will find that the color coded
> multiple wire bundles are all soldered to the same spot within the case,
> so the tech answer to your question is yes as long as the single wire
> coming out of the power supply is large enough to safely carry the amount
> of current totaled up by the ten fans.
>
> Personally, I wouldn't do it with all ten fans... but would at least
> create two for five fans.
>
> Look on the fans for the specs... either amps (milliamps) or watts, and
> post that here if you can't determine the total amps that ten would
> pull... also post the voltage and wire "color" as that will determine if
> the fans are 12v or 5v ...which directly relates to the amps...and
> directly relates to the recommended wire size.
>
> Beverly Howard [MS MVP-Mobile Devices]
>
 
Vic Baron wrote:
> Thanx, Beverly - you've answered my question. Sort of what I thought but
> don't have a spare PS to dismantle <g>. Not a problem to spread the load and
> actually it's only 4 120mm fans, 2 90mm fans and a water pump. Everything
> else is SATA and the PCIx video card which have their own connectors.
>
> Thanx again,
>
> Vic
>


The Molex disk drive 1x4 connector, is Molex part number 8981-04P or
Tycoelectronics (Amp) 1-480424-0. I looked up the latter of the two
on tycoelectronics.com to get a rating. (Manual line wrapped to suit
my USENET server - it rejects postings with long lines.)

http://ecommas.tycoelectronics.com/commerce/DocumentDelivery/DDEController?Action=showdoc&
DocId=Specification+Or+Standard%7F108-1077%7FO%7Fpdf%7FEnglish%7FENG_SS_108-1077_O.pdf

On page 6 of the document, is a curve for the four position (1x4) connector.

The housing of the connector, melts at 105C. They draw a line on the chart,
at 25C room temp plus 30C of self heating. That line intersects the current
curves. The cable assembly can use various gauges of wire. If a heavy wire
is used, then 12 amps is safe. If a light wire is used, then 8 amps is safe.

Since the room temp could heat up, the nylon housing would still be safe if
the room temperature was 45C. (Cheap wire plays a part as well, and the
insulation on a cheap wire might be getting soft at that point. So the
wire used might even be a limiting factor.)

So, you total all the loads you plan on chaining off one connector, and
see if it exceeds those limits. If the power supply uses substantial looking
wire, then you could use more than 8 amps.

The six fans would be like nothing to that connector. I have a 120mm fan that
draws 1 amps of current, and six of those is still OK. There are "Stealth"
fans, which move much less air, and they take 0.1 amp or less each.

A water pump probably has an ampere rating on the side of it, and you can
judge for yourself, whether a separate connector is justified for it.

Motors draw extra current during startup, but the duration of the
startup is probably not long enough to melt anything.

The SATA connectors on the other hand, are probably gutless in the
current carrying department, so for those people who use SATA to
1x4 converter cables, to get more 1x4's for case wiring, watch out.

HTH,
Paul

>
> "Beverly Howard [Ms-MVP/MobileDev]" <BevNoSpamBevHoward.com> wrote in
> message news:Ow8gC%23M5HHA.4164@TK2MSFTNGP04.phx.gbl...
>>>> would there be any problem it attaching 10 120mm fans to one

>> of the connectors as opposed to spreading them out over several? <<
>>
>> First, you have to take full responsibility for doing anything like this,
>> but...
>>
>> If you open most power supplies, you will find that the color coded
>> multiple wire bundles are all soldered to the same spot within the case,
>> so the tech answer to your question is yes as long as the single wire
>> coming out of the power supply is large enough to safely carry the amount
>> of current totaled up by the ten fans.
>>
>> Personally, I wouldn't do it with all ten fans... but would at least
>> create two for five fans.
>>
>> Look on the fans for the specs... either amps (milliamps) or watts, and
>> post that here if you can't determine the total amps that ten would
>> pull... also post the voltage and wire "color" as that will determine if
>> the fans are 12v or 5v ...which directly relates to the amps...and
>> directly relates to the recommended wire size.
>>
>> Beverly Howard [MS MVP-Mobile Devices]
>>

>
>
 
"Beverly Howard [Ms-MVP/MobileDev]" <BevNoSpamBevHoward.com> wrote in
message news:Ow8gC%23M5HHA.4164@TK2MSFTNGP04.phx.gbl...
> >> would there be any problem it attaching 10 120mm fans to one

> of the connectors as opposed to spreading them out over several? <<
>
> First, you have to take full responsibility for doing anything like this,
> but...
>
> If you open most power supplies, you will find that the color coded
> multiple wire bundles are all soldered to the same spot within the case,
> so the tech answer to your question is yes as long as the single wire
> coming out of the power supply is large enough to safely carry the amount
> of current totaled up by the ten fans.
>
> Personally, I wouldn't do it with all ten fans... but would at least
> create two for five fans.
>
> Look on the fans for the specs... either amps (milliamps) or watts, and
> post that here if you can't determine the total amps that ten would
> pull... also post the voltage and wire "color" as that will determine if
> the fans are 12v or 5v ...which directly relates to the amps...and
> directly relates to the recommended wire size.
>


Also note that the starting current will be larger than the steady running
current. You set up must cope with the starting current for all 10 fans.

What on earth are you trying to cool?
 
"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message
news:46cd456f$1_1@glkas0286.greenlnk.net...
>
> "Beverly Howard [Ms-MVP/MobileDev]" <BevNoSpamBevHoward.com> wrote in
> message news:Ow8gC%23M5HHA.4164@TK2MSFTNGP04.phx.gbl...
>> >> would there be any problem it attaching 10 120mm fans to one

>> of the connectors as opposed to spreading them out over several? <<
>>
>> First, you have to take full responsibility for doing anything like this,
>> but...
>>
>> If you open most power supplies, you will find that the color coded
>> multiple wire bundles are all soldered to the same spot within the case,
>> so the tech answer to your question is yes as long as the single wire
>> coming out of the power supply is large enough to safely carry the amount
>> of current totaled up by the ten fans.
>>
>> Personally, I wouldn't do it with all ten fans... but would at least
>> create two for five fans.
>>
>> Look on the fans for the specs... either amps (milliamps) or watts, and
>> post that here if you can't determine the total amps that ten would
>> pull... also post the voltage and wire "color" as that will determine if
>> the fans are 12v or 5v ...which directly relates to the amps...and
>> directly relates to the recommended wire size.
>>

>
> Also note that the starting current will be larger than the steady running
> current. You set up must cope with the starting current for all 10 fans.
>
> What on earth are you trying to cool?
>
>


LOL! I exaggerated a wee bit. I have a case with a built in liquid cooler.
The case radiator has 3 - 120 fans. There are two 120 fans for case intake
and exhaust. A top mounted 90mm fan for case exhaust and another 90mm for hd
cage cooling.

With liquid cooling one needs to keep the case cool to aid in cooling the
mobo because there is no CPU fan. Also I plan to try to overclock the system
a bit and that will bring temps up.

What surprises me is that with all the fans above plus the water pump and
the chip fan for the Northbridge, the new system is much quieter than my
stock P4 3.4 with the older style fans and power supply.

Vic
 
"Vic Baron" <vgbaron@hotmail.com> wrote in message
news:e$YYhzM5HHA.5164@TK2MSFTNGP05.phx.gbl...
>
> I have an 850W PS. Thinking of this like a typical house circuit with a
> 100 amp main and 30 amp circuits where you can overload a circuit but not
> blow the main...... would there be any problem it attaching 10 120mm fans
> to one of the connectors as opposed to spreading them out over several?
>
> Trying to keep the case wiring minimal and if I can connect all the fans
> on one power cable it would help.
>
> Thanx
> --
> There are 10 kinds of people - those who understand binary and those who
> don't
>


The PC power supply has no real analogy to a residential AC circuit.

The only time I've run into a balance requirement is when I had a relatively
adequate power supply, and many hard drives, CD rom, floppy,
magnetic-optical drive running off the molex connectors from the power
supply. That was several years ago. But, it stuck, and try to do so if
possible.

Current consumed by fans at startup, and when running afterwards is
negligible. Not to be concerned with the balance requirement I speak of.

The total wattage of power supply means nothing in the scheme of things in
the specific question. Fans use +12V, amperage total delivery on this leg
and other device uses of this is part of the total picture. There's also
the 3.3V concern regarding bios/OS application control of those fans. The
remainder of what the 850W power supply capabilities in null regarding your
question.
Dave
 
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