11 Jul
2005
11 Jul
'05
4:48 p.m.
My DEC dealer has a RA82 he wants $200 for, and I was thinking of trading
him one of my RL02s for it. That's what actually came in this chassis, but
I'm really concerned about the power requirements of the disk and
controller - I know the KDA50 is a pig, but I do have a separate expansion
box for it. My real concern is blowing a breaker in my apartment building.
Now, I've read the current surge draw on a RA81 (in the RA81 user guide) is
35A in 110V mode. Is this correct?
Also, what are my power bills going to look like running this thing 24/7? A
already run one RL02 and the CPU 24/7, and I'm talking about adding an
expansion box to it with the KDA50...will I be OK on one 15A circuit? Logic
with these numbers says no, but I saw somewhere on the web where a guy said
he was running an 11/750, RA82, and some other stuff all off 1 15A circuit.
The only way I can see this working is if the drive spins up somehow by
trickle charging a cap(or more than just 1) and then spinning up the drive.
Can anyone shed any light on this? Will I blow something with this RA disk
on my setup?
Thanks
Julian
11 Jul
11 Jul
4:54 p.m.
I used to run a MVII with an RA82 all plugged in to a cheapie powerstrip
without tripping it. Of course, you had to turn on the drive, wait for
it to settle and then power up everything else.
As far as power costs go...beats me, I kept it at work and let them pay
for it :)
Brian
On Mon, 2005-07-11 at 11:48 -0500, Julian Wolfe wrote:
My DEC dealer has a RA82 he wants $200 for, and I was
thinking of trading
him one of my RL02s for it. That's what actually came in this chassis, but
I'm really concerned about the power requirements of the disk and
controller - I know the KDA50 is a pig, but I do have a separate expansion
box for it. My real concern is blowing a breaker in my apartment building.
Now, I've read the current surge draw on a RA81 (in the RA81 user guide) is
35A in 110V mode. Is this correct?
Also, what are my power bills going to look like running this thing 24/7? A
already run one RL02 and the CPU 24/7, and I'm talking about adding an
expansion box to it with the KDA50...will I be OK on one 15A circuit? Logic
with these numbers says no, but I saw somewhere on the web where a guy said
he was running an 11/750, RA82, and some other stuff all off 1 15A circuit.
The only way I can see this working is if the drive spins up somehow by
trickle charging a cap(or more than just 1) and then spinning up the drive.
Can anyone shed any light on this? Will I blow something with this RA disk
on my setup?
Thanks
Julian
5:12 p.m.
For the sake of your home, I would recommend getting another additional
circuit into your computer room, most homes (unless you request and pay
for) have 15a rated circuit wiring and can carry 20a loads if you
upgrade the breaker, but if you go above that you are now risking
overheat on your wiring and outlets and you could be risking a fire.
Curt
Julian Wolfe wrote:
My DEC dealer has a RA82 he wants $200 for, and I was
thinking of
trading him one of my RL02s for it. That's what actually came in this
chassis, but I'm really concerned about the power requirements of the
disk and controller - I know the KDA50 is a pig, but I do have a
separate expansion box for it. My real concern is blowing a breaker
in my apartment building. Now, I've read the current surge draw on a
RA81 (in the RA81 user guide) is 35A in 110V mode. Is this correct?
Also, what are my power bills going to look like running this thing
24/7? A already run one RL02 and the CPU 24/7, and I'm talking about
adding an expansion box to it with the KDA50...will I be OK on one 15A
circuit? Logic with these numbers says no, but I saw somewhere on
the web where a guy said he was running an 11/750, RA82, and some
other stuff all off 1 15A circuit. The only way I can see this working
is if the drive spins up somehow by trickle charging a cap(or more
than just 1) and then spinning up the drive.
Can anyone shed any light on this? Will I blow something with this RA
disk on my setup?
Thanks
Julian
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6:47 p.m.
On Mon, 11 Jul 2005, Curt @ Atari Museum wrote:
For the sake of your home, I would recommend getting
another additional
circuit into your computer room, most homes (unless you request and pay
for) have 15a rated circuit wiring and can carry 20a loads if you
upgrade the breaker, but if you go above that you are now risking
overheat on your wiring and outlets and you could be risking a fire.
NO! NO! NO! BAD ADVICE!
One should never replace a breaker with a higher rated one unless they are
sure the wiring can accomodate the increased amperage. A 15A breaker
requires 14 guage wire. A 20A breaker requires 12 guage wire. Putting a
20A breaker on 14 guage wire is flirting with disaster.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
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7:05 p.m.
Every time I open up the back of a monitor or computer power supply, I'm
flirting with Disaster! I'm a good flirt, I've been told. I dunno - it
seems a miracle to me that I'm still alive, in fact. ;-) Good advice ,
tho; if not the fact that it's probably not smart to re-wire the breaker,
it will certainly invalidate your insurance if anything ever happens in
your home, even if it's unrelated; the insurance company will find a way
to make it as such.
NO! NO! NO! BAD ADVICE!
One should never replace a breaker with a higher rated one unless they
are
sure the wiring can accomodate the increased amperage. A 15A breaker
requires 14 guage wire. A 20A breaker requires 12 guage wire. Putting
a
20A breaker on 14 guage wire is flirting with disaster.
--
Sellam Ismail Vintage Computer
Festival
-----------------------------------------------------------------------
-------
International Man of Intrigue and Danger
http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage
Computers ]
[ and academia at www.VintageTech.com || at
http://marketplace.vintage.org ]
7:29 p.m.
NO! NO! NO! BAD ADVICE!
One should never replace a breaker with a higher rated one unless they are
sure the wiring can accomodate the increased amperage. A 15A breaker
requires 14 guage wire. A 20A breaker requires 12 guage wire. Putting a
20A breaker on 14 guage wire is flirting with disaster.
I would not call it "flirting with disaster", but it is not a good
idea. The chances of a fire breaking out under this circumstance is damn
small, but it is there.
On the flip side, many homes are wired with 12 anyway, so the
replacement breakers are OK. Some codes require 12 wire for everyday
household circuits.
William Donzelli
aw288 at osfn.org
8:30 p.m.
>>>> "William" == William
Donzelli <aw288 at osfn.org> writes:
> NO! NO! NO! BAD ADVICE!
>
> One should never replace a breaker with a higher rated one unless
> they are sure the wiring can accomodate the increased amperage. A
> 15A breaker requires 14 guage wire. A 20A breaker requires 12
> guage wire. Putting a 20A breaker on 14 guage wire is flirting
> with disaster.
William> I would not call it "flirting with disaster", but it is not
William> a good idea. The chances of a fire breaking out under this
William> circumstance is damn small, but it is there.
William> On the flip side, many homes are wired with 12 anyway, so
William> the replacement breakers are OK.
So I've heard. I've seen it rarely if ever.
Note that 20 amp requires 12 gauge copper. In homes of the right
(wrong?) age, you may find 12 gauge aluminum -- that's legal only for
15 amps. If you want aluminum and 20 amps, you'll need 10 gauge --
plus components rated for aluminum wire, which are generally somewhere
between rare and nonexistent, and often very expensive.
paul
11:10 p.m.
Note that 20 amp requires 12 gauge copper. In homes
of the right
(wrong?) age, you may find 12 gauge aluminum -- that's legal only for
15 amps. If you want aluminum and 20 amps, you'll need 10 gauge --
plus components rated for aluminum wire, which are generally somewhere
between rare and nonexistent, and often very expensive.
Anyone living in a house with Al wiring should either move out or replace
it all with copper.
Awful stuff.
William Donzelli
aw288 at osfn.org
12 Jul
12 Jul
3:17 a.m.
Paul Koning wrote:
And this is a huge problem, potentially much more dangerous than
undergauge wire (as in more likely to cause problems; maybe not likely
to cause more problems).
I lived in a duplex with clad aluminum wiring and copper-rated
breakers, fixtures, and wire nuts. I discovered this when replacing my
porch light fixture. I touched the earth ground lead, and got the
poopie shocked out of me. I thought I must have brushed a "hot" wire,
and got more poopie shocked out of me. The house was carrying 55V on
the earth ground.
Doc
>>>>"William" == William Donzelli <aw288 at osfn.org> writes:
> NO! NO! NO! BAD ADVICE!
>
> One should never replace a breaker with a higher rated one unless
> they are sure the wiring can accomodate the increased amperage. A
> 15A breaker requires 14 guage wire. A 20A breaker requires 12
> guage wire. Putting a 20A breaker on 14 guage wire is flirting
> with disaster.
William> I would not call it "flirting with disaster", but it is not
William> a good idea. The chances of a fire breaking out under this
William> circumstance is damn small, but it is there.
William> On the flip side, many homes are wired with 12 anyway, so
William> the replacement breakers are OK.
So I've heard. I've seen it rarely if ever.
Note that 20 amp requires 12 gauge copper. In homes of the right
(wrong?) age, you may find 12 gauge aluminum -- that's legal only for
15 amps. If you want aluminum and 20 amps, you'll need 10 gauge --
plus components rated for aluminum wire, which are generally somewhere
between rare and nonexistent, and often very expensive.
1:22 p.m.
I shudder when I picture aluminum core wiring... I just have visions
of it evaporating under load! :-)
Good solid copper 12 guage is the only way to go!
Curt
Doc Shipley wrote:
Paul Koning wrote:
And this is a huge problem, potentially much more dangerous than
undergauge wire (as in more likely to cause problems; maybe not likely
to cause more problems).
I lived in a duplex with clad aluminum wiring and copper-rated
breakers, fixtures, and wire nuts. I discovered this when replacing
my porch light fixture. I touched the earth ground lead, and got the
poopie shocked out of me. I thought I must have brushed a "hot" wire,
and got more poopie shocked out of me. The house was carrying 55V on
the earth ground.
Doc
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>>>> "William" == William Donzelli <aw288 at osfn.org>
writes:
>>>
> NO! NO! NO! BAD ADVICE!
> >> One should never replace a breaker with a higher rated one
unless
> they are sure the wiring can accomodate the
increased amperage. A
> 15A breaker requires 14 guage wire. A 20A breaker requires 12
> guage wire. Putting a 20A breaker on 14 guage wire is flirting
> with disaster.
William> I would not call it "flirting with disaster", but it is not
William> a good idea. The chances of a fire breaking out under this
William> circumstance is damn small, but it is there.
William> On the flip side, many homes are wired with 12 anyway, so
William> the replacement breakers are OK.
So I've heard. I've seen it rarely if ever.
Note that 20 amp requires 12 gauge copper. In homes of the right
(wrong?) age, you may find 12 gauge aluminum -- that's legal only for
15 amps. If you want aluminum and 20 amps, you'll need 10 gauge --
plus components rated for aluminum wire, which are generally somewhere
between rare and nonexistent, and often very expensive.
1:31 p.m.
I shudder when I picture aluminum core wiring... I
just have visions
of it evaporating under load! :-)
I am not sure how old youor house is, but beware - lots in the town have
(or had) Al. Mine did (rather, I am still yanking it out).
One of the big problems with Aluminum is that it flows under pressure -
the pressure of a screw, for example. Tighten down a screw on a fixture,
and next year, you will probably be able to tighten a little more. Then
next year, a little more.
William Donzelli
aw288 at osfn.org
2:12 p.m.
On 7/12/05, William Donzelli <aw288 at osfn.org> wrote:
Wasn't that popular to install in the 1970s?
While I have no Al wiring in my 90-year-old house, I do have
knob-and-tube, which is why I ran two new 15A circuits to the back
bedroom for the computers.
-ethan
I shudder when
I picture aluminum core wiring... I just have visions
of it evaporating under load! :-)
I am not sure how old youor house is, but beware - lots in the town have
(or had) Al. Mine did (rather, I am still yanking it out).
2:39 p.m.
>>>> "Ethan" == Ethan Dicks
<ethan.dicks at gmail.com> writes:
Ethan> On 7/12/05, William Donzelli <aw288 at osfn.org> wrote:
> > I shudder when I picture aluminum core
wiring... I just have
> visions > of it evaporating under load! :-)
>
> I am not sure how old youor house is, but beware - lots in the
> town have (or had) Al. Mine did (rather, I am still yanking it
> out).
Ethan> Wasn't that popular to install in the 1970s?
Yes, either copper clad (which is supposedly acceptable in
copper-rated devices -- at least in a lot of them) and plain aluminum,
which definitely requires nonstandard devices.
It's still very common in the really big stuff (the 0000 gauge wire
coming into new homes is probably Al) and that's probably ok. Then
again, I use copper everywhere -- even for that big wire for the
welder...
paul
4:03 p.m.
Ethan Dicks wrote:
On 7/12/05, William Donzelli <aw288 at osfn.org>
wrote:
Wasn't that popular to install in the 1970s?
While I have no Al wiring in my 90-year-old house, I do have
knob-and-tube, which is why I ran two new 15A circuits to the back
bedroom for the computers.
-ethan
Many years ago (30+), my grandmothers house was wired by running
cloth covered wires on insulators (like you see used for electric fences)
inside the house. (not inside the walls) One wire on each side of the
insulator. (No 3rd ground wire either)
Want to try hooking up a mainframe using that type of wiring?
I shudder
when I picture aluminum core wiring... I just have visions
of it evaporating under load! :-)
I am not sure how old youor house is, but beware - lots in the town have
(or had) Al. Mine did (rather, I am still yanking it out).
4:33 p.m.
On 7/12/05, Kevin Handy <kth at srv.net> wrote:
I wrote:
That's like knob and tube. For those not so blessed, the nail-in
insulators are the knobs, and the tubes are long ceramic tubes used as
bushings through wood structural elements and metal ducting (yes, the
wires go _through_ the ducting, not around). Part of the standard
installation practice was to run the hot and neutral on opposite sides
of the same joist where possible, but I have seen two parallel wires
through the same knob, especially before corners, etc.
Have to admit, though, that except for basements and attics, I've
always seen that kind of wiring _inside_ the walls (or threaded
through former gas-light pipes). I've never seen a ground wire with
knob and tube. AFAIK, that didn't even come into fashion when they
switched to asphalt-impregnated cloth-covered Romex (1940s?). I think
ground wires became standard in my area post 1960, with the advent of
plastic-covered Romex.
While I have no Al wiring in my 90-year-old house,
I do have
knob-and-tube
Many years ago (30+), my grandmothers house was wired by running
cloth covered wires on insulators (like you see used for electric fences)
inside the house. (not inside the walls) One wire on each side of the
insulator. (No 3rd ground wire either) Want to try hooking up a mainframe using that type of
wiring?
Um... no! At least you'd be able to see the insulation failing as it
smoked. ;-)
-ethan
5:20 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
On Tue, 12 Jul 2005, Ethan Dicks wrote:
Have to admit, though, that except for basements and
attics, I've
always seen that kind of wiring _inside_ the walls (or threaded
through former gas-light pipes). I've never seen a ground wire with
knob and tube. AFAIK, that didn't even come into fashion when they
switched to asphalt-impregnated cloth-covered Romex (1940s?). I think
ground wires became standard in my area post 1960, with the advent of
plastic-covered Romex.
I once helped a friend wire a new T1 for his ISP. His office is located
in a real old building with knob & tube wiring. Being the most limber, I
agreed to go up into the attic and crawl around amongst the wiring to run
the cable through. That was scary, as I had no idea if the wires were
live or not and my friend's reassurance that the power was shut off didn't
seem to be based on any factual knowledge. Very disconcerting.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
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6:32 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
AC "zaps" for a 10th of second at 110v isn't too bad when crawling
around running wires, it smarts and leave a nasty tingling feeling in
your teeth, makes you super wary the rest of the day.
What is the most painful is hooking up a telco line (I used to work for
an alarm company many many moons ago) and it just never failed that when
you were wiring up the RJ31X fail-over box to the alarm system, somebody
would call into the line and man does DC hurt and burn like a
Mother-f'er!!! (RJ31X's are great little boxes that will fail the
telco line over to the alarm box and cut the phone service to the rest
of the house, this is good in case someone has left a phone off the hook
or a burglar rushes in and starts punching numbers on the a telephones
keypad to force the alarm to misdial the central station).
Curt
Vintage Computer Festival wrote:
On Tue, 12 Jul 2005, Ethan Dicks wrote:
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Version: 7.0.323 / Virus Database: 267.8.13/47 - Release Date: 7/12/2005
Have to admit, though, that except for basements
and attics, I've
always seen that kind of wiring _inside_ the walls (or threaded
through former gas-light pipes). I've never seen a ground wire with
knob and tube. AFAIK, that didn't even come into fashion when they
switched to asphalt-impregnated cloth-covered Romex (1940s?). I think
ground wires became standard in my area post 1960, with the advent of
plastic-covered Romex.
I once helped a friend wire a new T1 for his ISP. His office is located
in a real old building with knob & tube wiring. Being the most limber, I
agreed to go up into the attic and crawl around amongst the wiring to run
the cable through. That was scary, as I had no idea if the wires were
live or not and my friend's reassurance that the power was shut off didn't
seem to be based on any factual knowledge. Very disconcerting.
7:05 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
>>>> "curt" == curt <@ Atari
Museum" <curt at atarimuseum.com>> writes:
curt> AC "zaps" for a 10th of second at 110v isn't too bad when
curt> crawling around running wires, it smarts and leave a nasty
curt> tingling feeling in your teeth, makes you super wary the rest
curt> of the day.
curt> What is the most painful is hooking up a telco line (I used to
curt> work for an alarm company many many moons ago) and it just
curt> never failed that when you were wiring up the RJ31X fail-over
curt> box to the alarm system, somebody would call into the line and
curt> man does DC hurt and burn ...
Ring isn't DC. The steady state voltage on a phoneline is -48V DC
(give or take quite a lot; I think the spec says the max is -60).
Ring voltage is 10 Hz AC, around 100 volts.
paul
7:23 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
Still burns and leaves the God-awefullest metal taste in your mouth when
you get hit with a ring surge, You sure its AC? Doesn't make sense,
but voltage on my meter would jump up from 48-52vdc to around 78-80vdc
on the DVM
Curt
Paul Koning wrote:
--
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Checked by AVG Anti-Virus.
Version: 7.0.323 / Virus Database: 267.8.13/47 - Release Date: 7/12/2005
>>>>"curt" == curt <@ Atari Museum" <curt at
atarimuseum.com>> writes:
>>>>
>>>>
curt> AC "zaps" for a 10th of second at 110v isn't too bad when
curt> crawling around running wires, it smarts and leave a nasty
curt> tingling feeling in your teeth, makes you super wary the rest
curt> of the day.
curt> What is the most painful is hooking up a telco line (I used to
curt> work for an alarm company many many moons ago) and it just
curt> never failed that when you were wiring up the RJ31X fail-over
curt> box to the alarm system, somebody would call into the line and
curt> man does DC hurt and burn ...
Ring isn't DC. The steady state voltage on a phoneline is -48V DC
(give or take quite a lot; I think the spec says the max is -60).
Ring voltage is 10 Hz AC, around 100 volts.
paul
7:26 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
On Tue, 12 Jul 2005, Curt @ Atari Museum wrote:
Still burns and leaves the God-awefullest metal taste
in your mouth when
you get hit with a ring surge, You sure its AC? Doesn't make sense,
but voltage on my meter would jump up from 48-52vdc to around 78-80vdc
on the DVM
Yes, it's AC. That's why it hurts. DC would feel strange perhaps but not
like AC. The reason you saw voltage at 80VDC is because your digital
meter samples slowly.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
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7:51 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
Rumor has it that Vintage Computer Festival may have mentioned these words:
On Tue, 12 Jul 2005, Curt @ Atari Museum wrote:
Or -- some meters when set to DC and fed AC will measure the RMS [kinda
DC-equivalent value] voltage of the AC...
100+V AC * .707 = 70+V DC.
The equation for figuring RMS voltage on sine-wave AC is:
1/sqrt(2)
(I've seen up to 110V AC myself [more on hand-cranked military handsets],
so that would get awfully close to the 80V the OP saw...)
Just a thought,
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger | Anarchy doesn't scale well. -- Me
zmerch at 30below.com. |
SysAdmin, Iceberg Computers
Still burns and leaves the God-awefullest metal
taste in your mouth when
you get hit with a ring surge, You sure its AC? Doesn't make sense,
but voltage on my meter would jump up from 48-52vdc to around 78-80vdc
on the DVM
Yes, it's AC. That's why it hurts. DC would feel strange perhaps but not
like AC. The reason you saw voltage at 80VDC is because your digital
meter samples slowly. 
7:55 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
Or -- some meters when set to DC and fed AC will
measure the RMS
[kinda DC-equivalent value] voltage of the AC...
100+V AC * .707 = 70+V DC.
Not quite. When one sees (say) "120V AC", that 120V *is* the RMS
value; "120V" is actually 120/sqrt(.5) = about 170V peak. (Assuming a
pure sine wave, that is, which is close enough for practical purposes
when dealing with mains power.)
As for "kinda DC-equivalent", it *is* equivalent as far as mean power
delivered into a purely resistive load goes, which is why that measure
is used: 120 RMS volts AC into (say) 120 ohms will dissipate as much
power, long-term average, as 120 volts DC into the same load. (RMS
here stands for Root-Mean-Square, which is a thumbnail description of
the mathematics involved: it's the square root of the mean value of the
square of the instantaneous voltage. This is derived thus: let the
voltage, as a function of time, be v(t). The current into a load of
resistance r will then, by Ohm's law, be i(t)=v(t)/r and the power will
be i(t)v(t), or v(t)^2/r. If we now work let c be the constant DC
voltage necessary to dissipate the same amount of power, average, we
find that c^2/r=mean(v(t)^2)/r, leading directly to the RMS formula.
sqrt(2) comes into it because that's what the RMS computation produces
when v(t) is a pure sine wave.)
The equation for figuring RMS voltage on sine-wave AC
is: 1/sqrt(2)
Only if you start with the peak AC voltage, which is not what
voltmeters normally indicate when measuring AC voltages.
/~\ The ASCII der Mouse
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7:57 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
Roger,
Thanks dude, great to know ! :-)
Curt
Roger Merchberger wrote:
Rumor has it that Vintage Computer Festival may have
mentioned these
words:
--
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Checked by AVG Anti-Virus.
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On Tue, 12 Jul 2005, Curt @ Atari Museum wrote:
Or -- some meters when set to DC and fed AC will measure the RMS
[kinda DC-equivalent value] voltage of the AC...
100+V AC * .707 = 70+V DC.
The equation for figuring RMS voltage on sine-wave AC is:
1/sqrt(2)
(I've seen up to 110V AC myself [more on hand-cranked military
handsets], so that would get awfully close to the 80V the OP saw...)
Just a thought,
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger | Anarchy doesn't scale well. -- Me
zmerch at 30below.com. |
SysAdmin, Iceberg Computers
Still burns and leaves the God-awefullest metal
taste in your mouth
when
you get hit with a ring surge, You sure its
AC? Doesn't make
sense,
but voltage on my meter would jump up from
48-52vdc to around 78-80vdc
on the DVM
Yes, it's AC. That's why it hurts. DC would feel strange perhaps
but not
like AC. The reason you saw voltage at 80VDC is because your digital
meter samples slowly.
8:07 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
(I've seen up to 110V AC myself [more on
hand-cranked military
handsets],
so that would get awfully close to the 80V the OP saw...)
was our tester crawling under a tank?
-----Original Message-----
From: Roger Merchberger <zmerch at 30below.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Date: Tue, 12 Jul 2005 15:51:26 -0400
Subject: Re: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
> Rumor has it that Vintage Computer Festival may have mentioned these
> words:
> >On Tue, 12 Jul 2005, Curt @ Atari Museum wrote:
> >
> > > Still burns and leaves the God-awefullest metal taste in your mouth
> when
> > > you get hit with a ring surge, You sure its AC? Doesn't make
> sense,
> > > but voltage on my meter would jump up from 48-52vdc to around
> 78-80vdc
> > > on the DVM
> >
> >Yes, it's AC. That's why it hurts. DC would feel strange perhaps but
> not
> >like AC. The reason you saw voltage at 80VDC is because your digital
> >meter samples slowly.
>
> Or -- some meters when set to DC and fed AC will measure the RMS [kinda
> DC-equivalent value] voltage of the AC...
>
> 100+V AC * .707 = 70+V DC.
>
> The equation for figuring RMS voltage on sine-wave AC is:
> 1/sqrt(2)
>
(I've seen up to 110V AC myself [more on
hand-cranked military
handsets],
so that would get awfully close to the 80V the OP saw...)
>
> Just a thought,
> Roger "Merch" Merchberger
>
> --
> Roger "Merch" Merchberger | Anarchy doesn't scale well. -- Me
> zmerch at 30below.com. |
> SysAdmin, Iceberg Computers
>
7:36 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
yeah, it's AC alright. 20hz at 72volts is nothing to screw around with.
It's like riding a slow wave... it don't necessarily kill you... but it
sure does suck.
You know why it was 20hz / 72volts? Because it has to do with the way
that the original bells inside of the circuitry on a phone would react so
perfectly to that. I love em' old phones.
-----Original Message-----
From: "Curt @ Atari Museum" <curt at atarimuseum.com>
To: General at smtp5.suscom.net, "Discussion at smtp5.suscom.net":On-Topic and
Off-Topic Posts <cctalk at classiccmp.org>
Cc:
Date: Tue, 12 Jul 2005 15:23:35 -0400
Subject: Re: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
Still burns and leaves the God-awefullest metal taste
in your mouth
when
you get hit with a ring surge, You sure its AC? Doesn't make
sense,
but voltage on my meter would jump up from 48-52vdc to around 78-80vdc
on the DVM
Curt
Paul Koning wrote:
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>>>>"curt" == curt <@ Atari Museum" <curt at
atarimuseum.com>> writes:
>>>>
>>>>
curt> AC "zaps" for a 10th of second at 110v isn't too bad when
curt> crawling around running wires, it smarts and leave a nasty
curt> tingling feeling in your teeth, makes you super wary the rest
curt> of the day.
curt> What is the most painful is hooking up a telco line (I used to
curt> work for an alarm company many many moons ago) and it just
curt> never failed that when you were wiring up the RJ31X fail-over
curt> box to the alarm system, somebody would call into the line and
curt> man does DC hurt and burn ...
Ring isn't DC. The steady state voltage on a phoneline is -48V DC
(give or take quite a lot; I think the spec says the max is -60).
Ring voltage is 10 Hz AC, around 100 volts.
paul
9:53 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
On Tue, 12 Jul 2005, Curt @ Atari Museum wrote:
AC "zaps" for a 10th of second at 110v
isn't too bad when crawling
. . .
would call into the line and man does DC hurt and burn
like a
last time that I checked, the spec called for 90VAC at 20 Hz.
... and YES, it Hertz.
10:16 p.m.
New subject: Somewhat OT Knob & Tube wiring (was Re: Power and the RA82)
Fred Cisin wrote:
last time that I checked, the spec called for 90VAC at 20 Hz.
... and YES, it Hertz.
Well 20 HZ is the low end of HI-FI so don't ignore it. :)
However for some reason I still like a mechanical bell
better for a phone than all the singing and dancing stuff
you get with a modern phone.
5:14 p.m.
>>>> "Kevin" == Kevin Handy
<kth at srv.net> writes:
Kevin> Many years ago (30+), my grandmothers house was wired by
Kevin> running cloth covered wires on insulators (like you see used
Kevin> for electric fences) inside the house. (not inside the walls)
Kevin> One wire on each side of the insulator. (No 3rd ground wire
Kevin> either)
That's "knob & tube". Fine stuff, just freaky looking to the modern
mind.
Kevin> Want to try hooking up a mainframe using that type of wiring?
No problem if the current rating is adequate.
paul
13 Jul
13 Jul
2:14 a.m.
On Tue, 12 Jul 2005 10:03:14 -0600
Kevin Handy <kth at srv.net> wrote:
Ethan Dicks wrote:
I've never powered up anything bigger than a quad pentium-pro server on
the 'knob and tube' (what you described) wiring in my house. I do aim
to sometime not to far off start messing with the SparcServer 1000. But
wouldn't you need three phase power and/or 220 volt service for most
'real' mainframes? (I have three phase outputs on my Homelite Gasoline
generator)
On 7/12/05, William Donzelli <aw288 at
osfn.org> wrote:
I am not sure how old youor house is, but beware - lots in the town
have>(or had) Al. Mine did (rather, I am still yanking it out).
Wasn't that popular to install in the 1970s?
While I have no Al wiring in my 90-year-old house, I do have
knob-and-tube, which is why I ran two new 15A circuits to the back
bedroom for the computers.
-ethan
Many years ago (30+), my grandmothers house was wired by running
cloth covered wires on insulators (like you see used for electric
fences) inside the house. (not inside the walls) One wire on each side
of the insulator. (No 3rd ground wire either)
Want to try hooking up a mainframe using that type of wiring?
>I shudder when I picture aluminum core
wiring... I just have
visions>>of it evaporating under load! :-)
4:07 a.m.
Scott Stevens declared on Tuesday 12 July 2005 09:14 pm:
On Tue, 12 Jul 2005 10:03:14 -0600
Uhm, you don't have 220V service to your house? I don't think I'd
consider moving into a house that doesn't have at least 100A, 240V
service. And even then, the 100A service would get upgrade to 240V
service fairly soon after I moved in...
Pat
--
Purdue University ITAP/RCAC --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
Want to try hooking up a mainframe using that
type of wiring?
But wouldn't you need three phase power and/or 220 volt service
for most 'real' mainframes? (I have three phase outputs on my
Homelite Gasoline generator)
4:41 a.m.
Patrick Finnegan declared on Tuesday 12 July 2005 11:07 pm:
Scott Stevens declared on Tuesday 12 July 2005 09:14
pm:
Blah, I meant "the 100A service would get upgraded to 200A service"
Pat
--
Purdue University ITAP/RCAC --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
On Tue, 12 Jul 2005 10:03:14 -0600
Uhm, you don't have 220V service to your house? I don't think I'd
consider moving into a house that doesn't have at least 100A, 240V
service. And even then, the 100A service would get upgrade to 240V
service fairly soon after I moved in... Want to try hooking up a mainframe using that
type of wiring?
But wouldn't you need three phase power and/or 220 volt service
for most 'real' mainframes? (I have three phase outputs on my
Homelite Gasoline generator)
10:41 p.m.
On Tue, 12 Jul 2005 23:07:31 -0500
Patrick Finnegan <pat at computer-refuge.org> wrote:
Scott Stevens declared on Tuesday 12 July 2005 09:14
pm:
Of course there's 240 volt service. There wasn't a few weeks ago when a
tree limb took out just one of the wires coming in, but there normally
is.
On Tue, 12 Jul 2005 10:03:14 -0600
Uhm, you don't have 220V service to your house? I don't think I'd
consider moving into a house that doesn't have at least 100A, 240V
service. And even then, the 100A service would get upgrade to 240V
service fairly soon after I moved in...
Want to try hooking up a mainframe using that
type of wiring?
But wouldn't you need three phase power and/or 220 volt service
for most 'real' mainframes? (I have three phase outputs on my
Homelite Gasoline generator) Pat
--
Purdue University ITAP/RCAC --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
1:30 p.m.
>>>> "Scott" == Scott Stevens
<chenmel at earthlink.net> writes:
Scott> I've never powered up anything bigger than a quad pentium-pro
Scott> server on the 'knob and tube' (what you described) wiring in
Scott> my house. I do aim to sometime not to far off start messing
Scott> with the SparcServer 1000. But wouldn't you need three phase
Scott> power and/or 220 volt service for most 'real' mainframes? (I
Scott> have three phase outputs on my Homelite Gasoline generator)
Three phase, on a Homelite? Are you sure? Mid size generators often
have twist lock outlets -- not for three phase, but for 220 at 30+
amps with neutral and ground. My Honda has that. The pin
configuration on the outlet will tell you what it is, or the manual...
Yes, "real" mainframes typically need three phase. You can make it
from one phase, either with a rotary converter
(basically a 3 phase
motor that synthesizes the missing phase from one phase power)
or a
solid state converter. Either is commonly used by metalshop people
who need to power 3 phase lathes and such. And of course you need a
fat enough service coming into the house; a knob & tube wired house
may well have 60 amp, or maybe even 30 amp, service, and that
certainly won't feed the KL10 in the barn.
Some especially real mainframes want 3 phase 400 Hz power -- CDC in
particular. If you have their motor generators that's taken care of;
if not, then most solid state converters ("motor speed control") will
be able to produce that.
paul
10:44 p.m.
On Wed, 13 Jul 2005 09:30:14 -0400
Paul Koning <pkoning at equallogic.com> wrote:
It's labelled 3 phase. This is not a consumer-grade Homelite, it's a
big old one bought at a farm auction. It has a metal property tag so
was probably industrial or military before the previous owner bought it.
>>>> "Scott" == Scott Stevens <chenmel at earthlink.net>
writes:
Scott> I've never powered up anything bigger than a quad pentium-pro
Scott> server on the 'knob and tube' (what you described) wiring in
Scott> my house. I do aim to sometime not to far off start messing
Scott> with the SparcServer 1000. But wouldn't you need three phase
Scott> power and/or 220 volt service for most 'real' mainframes? (I
Scott> have three phase outputs on my Homelite Gasoline generator)
Three phase, on a Homelite? Are you sure? Mid size generators often
have twist lock outlets -- not for three phase, but for 220 at 30+
amps with neutral and ground. My Honda has that. The pin
configuration on the outlet will tell you what it is, or the manual...
12 Jul
12 Jul
1:33 p.m.
New subject: IBM Cad/Cam System on Ebay...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=74946&item=5…
Not mine.... looks interesting, great starting bid price, no reserve.
Curt
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1:35 p.m.
New subject: Nice Xerox 820 System...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4193&item=52…
$9.99 opening bid, no reserve.... not mine, looks like a good deal.
Curt
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11 Jul
11 Jul
9:39 p.m.
On Mon, 11 Jul 2005, William Donzelli wrote:
I would not take the chance, personally. Maybe it's because I own my home
and I happen to like living in it and all the stuff I've accumulated thus
far in my life ;) It's not that much work to run the correct wiring.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
NO! NO! NO!
BAD ADVICE!
One should never replace a breaker with a higher rated one unless they are
sure the wiring can accomodate the increased amperage. A 15A breaker
requires 14 guage wire. A 20A breaker requires 12 guage wire. Putting a
20A breaker on 14 guage wire is flirting with disaster.
I would not call it "flirting with disaster", but it is not a good
idea. The chances of a fire breaking out under this circumstance is damn
small, but it is there.
9:51 p.m.
On 7/11/05, Vintage Computer Festival <vcf at siconic.com> wrote:
I would not take the chance, personally. Maybe
it's because I own my home
and I happen to like living in it and all the stuff I've accumulated thus
far in my life ;) It's not that much work to run the correct wiring.
Agreed. I installed a 30A breaker, and a Hubbel Twist-n-Lock 30A
receptacle in my basement to power the 8300. No short cuts there.
-ethan
9:58 p.m.
On 7/11/05, Vintage Computer Festival <vcf at siconic.com> wrote:
I would not take the chance, personally. Maybe
it's because I own my home
and I happen to like living in it and all the stuff I've accumulated thus
far in my life ;) It's not that much work to run the correct wiring.
Not to mention that if there were a problem, the insurance company might
not pay the claim, indicating the person who replaced the breaker with
the incorrect value as liable...
--tom
10:07 p.m.
indicating the person who replaced the breaker with
the incorrect
value as liable...
On a tangential note, is it possible to "lean" on a typical household
breaker to stop it from tripping? Sort-of-like "battle override" on
a Navy ship... Or is the lever only good for resetting, and holding
it will not stop it from tripping? I think the latter but I've never
tried it for real.
Tim.
11:17 p.m.
On a tangential note, is it possible to
"lean" on a typical household
breaker to stop it from tripping? Sort-of-like "battle override" on
a Navy ship... Or is the lever only good for resetting, and holding
it will not stop it from tripping? I think the latter but I've never
tried it for real.
Some yes, some no. I think most new designs are "no".
Breakers are notoriously variable when it comes to trip current, so if you
have patience, you can swap around breakers until you find one that gives
you that little bit of extra forgiveness.
William Donzelli
aw288 at osfn.org
11:43 p.m.
On a tangential note, is it possible to
"lean" on a typical household
breaker to stop it from tripping? Sort-of-like "battle override" on
a Navy ship... Or is the lever only good for resetting, and holding
it will not stop it from tripping? I think the latter but I've never
tried it for real.
I have an idea that it's a requirement in the UK that you can't do this
-- if the lever is jammed in the 'on' position, the breaker will still
trip. Certainly alkl those of reputable manufacture behave this way (you
can try holding the lever of an RCD in the 'on' position and pressing the
test button, it will still trip).
-tony
12 Jul
12 Jul
10:19 p.m.
On Mon, 11 Jul 2005, Tim Shoppa wrote:
On a tangential note, is it possible to
"lean" on a typical household
breaker to stop it from tripping? Sort-of-like "battle override" on
a Navy ship... Or is the lever only good for resetting, and holding
it will not stop it from tripping? I think the latter but I've never
tried it for real.
Sure, but why not just take the breaker out and twist the two ends
together with black tape? Only slightly less safe... :-)
11 Jul
11 Jul
11:15 p.m.
I would not take the chance, personally. Maybe
it's because I own my home
and I happen to like living in it and all the stuff I've accumulated thus
far in my life ;) It's not that much work to run the correct wiring.
Nor would I - but I am a son of a Chicago hospital electrician. I still
use thinwall and BX (and even got exposed to thickwall a weekend ago).
It is not much work, but for anyone that does this, please research the
project so everything is code. Too many people take shortcuts.
William Donzelli
aw288 at osfn.org
12 Jul
12 Jul
12:04 a.m.
On Mon, 11 Jul 2005 19:15:03 -0400 (EDT)
William Donzelli <aw288 at osfn.org> wrote:
We have knob and tube wiring in part of our house here, and scanty, if
any, grounding. The switchbox/fusebox is bolted to the outside of the
house in the back porch, and newer upgrade boxes and switches cascade
down the wall beneath the original, which appears to be from the 1920's.
This place was built in 1900 and the wiring and other fancy stuff like
running water were added years later.
I *do* need to upgrade the wiring and service sometime soon. There are
places in the cellar (which is beneath only one room of the house) where
the wiring, although quite sound as far as I can estimate, is very scary
looking.
I would not
take the chance, personally. Maybe it's because I own
my home and I happen to like living in it and all the stuff I've
accumulated thus far in my life ;) It's not that much work to run
the correct wiring.
Nor would I - but I am a son of a Chicago hospital electrician. I
still use thinwall and BX (and even got exposed to thickwall a weekend
ago).
It is not much work, but for anyone that does this, please research
the project so everything is code. Too many people take shortcuts.
2:16 p.m.
>>>> "Scott" == Scott Stevens
<chenmel at earthlink.net> writes:
Scott> On Mon, 11 Jul 2005 19:15:03 -0400 (EDT) William Donzelli
Scott> <aw288 at osfn.org> wrote:
> > I would not take the chance, personally.
Maybe it's because I
> own > my home and I happen to like living in it and all the stuff
> I've > accumulated thus far in my life ;) It's not that much work
> to run > the correct wiring.
>
> Nor would I - but I am a son of a Chicago hospital electrician. I
> still use thinwall and BX (and even got exposed to thickwall a
> weekend ago).
>
> It is not much work, but for anyone that does this, please
> research the project so everything is code. Too many people take
> shortcuts.
>
Scott> We have knob and tube wiring in part of our house here, and
Scott> scanty, if any, grounding. The switchbox/fusebox is bolted to
Scott> the outside of the house in the back porch, and newer upgrade
Scott> boxes and switches cascade down the wall beneath the original,
Scott> which appears to be from the 1920's. This place was built in
Scott> 1900 and the wiring and other fancy stuff like running water
Scott> were added years later.
Scott> I *do* need to upgrade the wiring and service sometime soon.
Scott> There are places in the cellar (which is beneath only one room
Scott> of the house) where the wiring, although quite sound as far as
Scott> I can estimate, is very scary looking.
Getting a copy of the Electric Code would be a good idea (also "Wiring
Simplified" by Richter, an excellent book). Knob & tube wiring is
still legal (though you can't install more of it) -- which is more
than I can say for some work I have seen in newer houses that was done
by people who are licensed -- and clearly do not deserve to be. Stuff
like grounding wires left unconnected in bathroom baseboard
heaters... yikes.
paul
11 Jul
11 Jul
5:25 p.m.
On 7/11/05, Julian Wolfe <fireflyst at earthlink.net> wrote:
My DEC dealer has a RA82 he wants $200 for, and I was
thinking of trading
him one of my RL02s for it. That's what actually came in this chassis, but
I'm really concerned about the power requirements of the disk and
controller - I know the KDA50 is a pig, but I do have a separate expansion
box for it. My real concern is blowing a breaker in my apartment building.
Now, I've read the current surge draw on a RA81 (in the RA81 user guide) is
35A in 110V mode. Is this correct?
The surge _is_ over 30A, but it seems to be brief enough that you
_should_ be OK re: tripping breakers, but my experience is in a house
where I _knew_ it was on its own circuit.
Steady-state draw is about 8A, so to avoid problems, power up the
drive, wait 30 sec to stabilize (should go faster than that, but
better safe than sorry), _then_ power up the rest of the system.
Unfortunately, in an apartment setting, it's possible you don't have
a) 12 ga wiring, and b) breakers feeding small numbers of outlets.
What if your neighbor (or you) fire up the microwave that's on the
same circuit...
Also, what are my power bills going to look like
running this thing 24/7? A
already run one RL02 and the CPU 24/7, and I'm talking about adding an
expansion box to it with the KDA50...will I be OK on one 15A circuit?
Power bills? An RA81 (similar draw to RA82) is about a 1000W device.
So just the drive alone is going to cost 24kWH per day to run - if
your rate is abour $0.11/kWH, that's $2.64/day for just the drive. I
have an 8300 in the basement with an RA81 and MBA 2.4GB SDI disk box.
I use the RA81 only as required (i.e., not much), and run things off
of the dual 5.25" ESDI drives in the MBA box. Much cheaper. I also
tend to run a uVAX-II more than the 8300 - same amount of RAM, and
with an RD54, not _too_ bad in terms of power/performance, but the
disk size limits me to VMS 6.1 (I think that's what's on it - haven't
used it in over a year with my travels). I could throw a KDA50 in
there, but as you point out, it would need its own expansion BA23 for
power (I have it, but haven't attached it).
So... figure on at least $3/day for the CPU and disks, more or less,
depending on your rates. You can see that after a couple of months,
you might as well drop the $200 or so on a Qbus SCSI controller...
you'll pay more than that in power plus the cost of the RA82. Options
include a smaller SDI drive (RA90, or a smaller still RA7x), or an
ESDI/SMD controller and a smaller drive than an RA82. If you already
_had_ the RA82, it might not be too bad, or if the RA82 were free. To
have to _pay_ $200 plus S&H, you might as well put that money towards
a Qbus SCSI controller and use an old 4GB SCSI drive. Cheaper in the
long run, and unless you have a thing for 100% DEC end-to-end, still a
period solution (and it will fit in the BA23!)
-ethan
9:31 p.m.
On 7/11/05, Tim Shoppa <shoppa_classiccmp at trailing-edge.com> wrote:
I will admit that I haven't measured it myself. Don't forget there
are several square feet of layered circuits in an RA81 - it's not just
the motor, but I'm willing to concede that the drive might not draw
the stated 8A @ 120VAC.
-ethan
Steady-state
draw is about 8A [RA81]
Even that's an over-estimate. I'd say a few hundred watts after
spin-up. That'd be 2-3A (modulo the power factor... there's a big
motor but the power factor cannot be all that bad could it?)
10:04 p.m.
might not draw the stated 8A @ 120VAC.
That's a "max" rating. Most DEC stuff from that era overstates
power consumption/cooling required by a factor of 2 or 3 for site
installation purposes.
Don't forget there are several square feet of
layered circuits
Oh, yeah, certainly. Some of it is VLSI, other (read channel)
is ECL-like, and it does draw power. But look at the little exhaust
fan on the back of the drive - it is not dissipating a kilowatt,
but a few hundred watts.
I got rid of all my RA8x stuff around about 1996 or so. But
I had no problem running 4 drives simultaneously on a 20A kitchen
circuit. (Sequenced spin-up, of course.) Along with a 11/730.
Tim.
7122
days inactive
7124
days old
49 comments
20 participants
participants (20)
-
ard＠p850ug1.demon.co.uk -
aw288＠osfn.org -
bdwheele＠indiana.edu -
bfranchuk＠jetnet.ab.ca -
chenmel＠earthlink.net -
cisin＠xenosoft.com -
computer＠officereach.net -
curt＠atarimuseum.com -
doc＠mdrconsult.com -
ethan.dicks＠gmail.com -
fireflyst＠earthlink.net -
kth＠srv.net -
mouse＠Rodents.Montreal.QC.CA -
pat＠computer-refuge.org -
pkoning＠equallogic.com -
shoppa_classiccmp＠trailing-edge.com -
tomj＠wps.com -
uban＠ubanproductions.com -
vcf＠siconic.com -
zmerch＠30below.com