Ya know -- that may lead to warning folks that kind of current can
be dangerous -- even at 7.5 volts. Fuses are your friend - use them
even though the p/s have a crowbar/over current protection on
output.
We had a Blade Enclosure at work with 6) 2300 Watt power supplies
that got 12V pin almost shorted -- the blade connector and FR4 were
charcoal and back plane had a large hole in it. The 21 fire trucks
that showed up were bit of surprise though.
The reason I say almost shorted -- there was something left.:-). The
12V bus can source around 1000 amps on the backplane since I don't
run redundancy. These are test chassis and this is Not something you
would see in the field.
And as a side note, they now run 6) 2700 Watt P/S. Engineering said
the 2300 W were too small. ROFLMAO.
ts
On 7/23/2012 7:36 PM, monahanz wrote:
Plus you can use it as a backup electric arc welder!
On Sunday, July 22, 2012 1:47:39 PM UTC-7, Terry wrote:
And for
those of us that want overkill I found this
1 x 350 Watt, Single Output, SE-350-7.5 from Mean Well
(SE-350-7.5) = $48.29
http://www.powergatellc.com/mean-well-se-350-75-power-supply.html
Output(s) 7.5V @ 46.00A
Power 350 Watts
Dimensions 8.46 x 4.53 x 1.97"
Operational Efficiency 80.00%
Operating Temperature -20-60°C
Total with shipping was around $62 so not bad.
Terry
-----Original Message-----
From: n8vem...@googlegroups.com
[mailto:n8vem-s100@googlegroups.com]
On
Behalf Of John Monahan
Sent: Sunday, July 22, 2012 3:29 PM
To: n8vem...@googlegroups.com
Subject: RE: [N8VEM-S100:1001] S-100 backplane request for help
Paul, 12A on the 7.5V may be a little on the low side unless you
are just
sticking to 8 bits. The 16 bit CPU boards have 3A regulators
and if you
have a dual (or more) CPU master slave setup, things could get
tight. Agree
20A's is probably best. The 16 V lines are really only used for
RS232 etc.
these days and even there, there are converter chips. So 1-2 A
is fine.
John
John Monahan Ph.D
e-mail: mon...@vitasoft.org
Text: mon...@txt.att.net
-----Original Message-----
From: n8vem...@googlegroups.com
[mailto:n8vem-s100@googlegroups.com]
On
Behalf Of Paul Birkel
Sent: Sunday, July 22, 2012 11:37 AM
To: n8vem...@googlegroups.com
Subject: Re: [N8VEM-S100:1000] S-100 backplane request for help
While John has some great information on his backplane/ps page
(http://s100computers.com/My%20System%20Pages/The%20Box/The%20Box.htm#The_Po
wer_Supply),
one point that is missing is the proper power supply sizing for
an 8-slot
system.
The IEEE 696:1983 spec is silent on the allowed/anticipated
ps-loading per
slot, but it seems reasonable to assume 1 A to maybe 1.5 A
average per slot
on the 8V rail, max (most cards hosting a single 1A +5V
regulator, with the
occasional dual-regulator configuration like the dual-IDE card)?
That
suggests maybe 12A on the 8V rail, and we might guess 1-2A max
on the +16
and -16V rails (since these aren't used much at all on modern
cards)?
Am I way off-base here?
FWIW, here are what appear to be the most relevant Meanwell
supplies (via
Power Factor, as pointed out by John) -- all of which can have
their output
voltages adjusted upwards a bit to fit the 8 and 16 volt
bus-targets:
http://www.power-factor-1st.com/g2-series/s-100f.html
7.5V, 0~13.5A $49.45
http://www.power-factor-1st.com/g2-series/s-150.html
7.5V, 0~20A $55.45
http://www.power-factor-1st.com/g2-series/s-210.html
7.5V, 0~27A $70.95
http://www.power-factor-1st.com/g2-series/s-40.html
15V, 0~2.8A $37.90
The 20A (second line) seems to be the cost-effective sweet-spot
"with
headroom".
Happy hunting :->.
On Sun, Jul 22, 2012 at 1:55 PM, Andrew Lynch <LYN...@yahoo.com> wrote:
> Hi! I’ve gotten a request for some help with the S-100
backplane PCB.
> Since it will probably require a PCB respin to fix I would
like to
> gather up all the feedback and incorporate them as best I
can. Thanks
> to Don Caprio there are some excellent builder instructions
here:
>
> http://n8vem-sbc.pbworks.com/w/page/35158565/Build%20Instructions
>
> Please post photos of your completed working S-100
backplane systems
> on the wiki in the S-100 backplane folder. Actual builder
photos are
> *very* helpful for new builders.
>
> http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder¶m=S-100%20b
> ackplane
>
> There is a new file for S-100 backplane fixes and
improvements here:
>
> http://n8vem-sbc.pbworks.com/w/page/55620344/S-100%20backplane%20impro
> vements%20and%20fixes
>
> Please edit with any issues you’ve encountered on how to
fix and/or
> improve the S-100 backplane.
>
> The photos that are in the folder at the moment are getting
rather
> dated so they should be retired to the archive as to not
confuse any new
builders.
>
> Thanks and have a nice day!
>
> Andrew Lynch
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