combining 2 power supplies

[James Sweet]

But I don't belive that 250 W drawn from the mains is a likely maximum now.

I was doing some calculuations the other day based on a pair of
Opterons. According to AMD, they are about 100 W each. A very mediocre
graphics card is probably 30 W. Disks take more when they spin up.

350 W is probably adequate for most things I would agree. My main PC (I
don't use PCs much) has a 235 W power supply in it, but a pair of 450
MHz Pentiums and a 10,000 rpm SCSI disk. That seems to be OK

A more elegant solution if there are multiple disks might be to build a
timer that delays the starts on them, as the power when running is
probalby only half that when starting.

Personally, I think I'd just rather buy a bigger psu - they are not that
expensive now.

How many people have a pair of Opterons though? I thought we were
talking consumer PCs?

 

[crazy frog]

log on to siliconchip type in pc power supplies
into the article search box, it will take you to the new
article,s but not the old one for the dummy loads.
i asked them for it but thay wont to charge me.
i will see if ican fined it in my folders.

 

[crazy frog]

thats what i read from silicon chip and have
done so and it works fine.
im useing a 200w one to power a 16/ch mixer
i have built in the last 2 years.
im useing a nother one power my modem
and network hub and some fans.

 

[Sam Goldwasser]

thats what i read from silicon chip and have
done so and it works fine.
im useing a 200w one to power a 16/ch mixer
i have built in the last 2 years.
im useing a nother one power my modem
and network hub and some fans.

http://www.formfactors.org/developer\specs\ATX12V_PSDG_2_2_public_br2.pdf

This appears to be Intel's ATX specifications. It is not clear what
minimum load is required for proper regulation. Under "DC Voltage
Regulation", it says:

"The DC output voltages shall remain within the regulation ranges shown
in Table 2 when measured at the load end of the output connectors under
all line, load, and environmental conditions."

Later on in: "No Load Operation", it says:

"No damage or hazardous condition should occur with all the DC output
connectors disconnected from the load. The power supply may latch into
the shutdown state."

Loading examples never go below 1 A on +12, 0.3 A on +5, 0.5 A on +3.3.

So, it shouldn't blow up under very light or no load conditions, but the
exact values needed for proper operation may not be obvious.

And, the existence of this specification document doesn't necessarily
imply that all Far East ATX power supplies are fully compliant.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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Important: Anything sent to the email address in the message header above is
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[Ian Stirling]

Thanks and I did my numbers:

I'm thinking a P4 9xx CPU and it draws around 100w alone, new display cards
(ATI x series) also draws a lot of power. More than 1 web site said hard
disks draws 25w so I use that in my calculation to be on the safe side.

Don't believe 'more than one website'.
Look at the specs for your drives.
The makers website will list exact startup currents.

 

[crazy frog]

i think you need some load to make it regulate properly

 

[crazy frog]

the article im talking obout is for at power sups
and cannot fined it online, i had it someware
will try to fined it.

 

[crazy frog]

i found the artile, its from december 1998
silicon chip.
on front page is has make use of that old pc
power supply.
min load 47ohm 1 watt resistor, ive tested it up to 100ohm
and is ok.

 

[Sam Goldwasser]

i found the artile, its from december 1998 silicon chip.
on front page is has make use of that old pc power supply.
min load 47ohm 1 watt resistor, ive tested it up to 100ohm and is ok.

So what? Does it say the specification allows for that high a resistor
or just that someone did a project and it worked, and you did a project
and it worked? The article doesn't appear to be archived, so are you
going to share what it says?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[crazy frog]

i sed i tested it up to 100ohm.
if you dont beleave me, just bloody try it.

look i have done it and it works.
the fuckin aticle is in my hand.

if dont beleave me then, its youre bloody
loss.

 

[crazy frog]

if i had youre real email address
i can send these pages to you
but i havent.

 

[Sam Goldwasser]

i sed i tested it up to 100ohm.
if you dont beleave me, just bloody try it.

look i have done it and it works.
the fuckin aticle is in my hand.

if dont beleave me then, its youre bloody
loss.

And you've tried it on how many different manufacturer's power supplies?

You can contact me via the link below.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[crazy frog]

yes i have

 

[crazy frog]

how do i send the pages of the artile.
how do attach them.
do you have a email address to send them.
like a hotmail.

 

[Sam Goldwasser]

how do i send the pages of the artile.
how do attach them.
do you have a email address to send them.
like a hotmail.

You contact me via my Web site and I'll reply with a valid email address.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[crazy frog]

ok but im not soure if silicon chip will
let send copies of ther aticles based on copyright
laws.

 

[crazy frog]

the silicon chip aricles are copyright
i cannot send it.
but just take my word for it.
47ohm to 100ohm.
or you will have to log on to them and
ask them.
sorry about that.