>
> Date: Wed, 5 May 2021 00:03:05 -0700
> From: Josh Dersch
> Subject: PDP-8/I Negative-bus termination
>
> Hey all --
>
> Until this point I've never had any peripherals for my negibus systems
> (apart from teletypes), and it occurs to me that I have no idea if the bus
> needs to be terminated (
>
> Date: Wed, 5 May 2021 13:20:59 +0100
> From:
> Subject: RE: Motor generator
>
> We had a Motor/Generator for our Honeywell L66. Not sure it was because it
> wanted US voltages or just for a clean supply
> Dave
>
I also worked on a Honeywell L66 that had two motor-generators. We used one
at a
On 5/5/21 6:40 PM, Jay Jaeger via cctalk wrote:
>
> While I was in grad school at U.W. (the one in Wisconsin) we had
> obtained via surplus an IBM 7094 II from military surplus - I seem to
> recall WSMR (White Sands Missle Range). Of course, it had an MG. We
> got it put together and with a repl
On 5/5/2021 7:18 PM, Jules Richardson via cctalk wrote:
On 5/5/21 6:09 AM, Mark Linimon via cctalk wrote:
On Tue, May 04, 2021 at 10:07:28PM -0700, Chuck Guzis via cctech wrote:
"Power for the basic computer consists of one 250 kva, 400 Hz motor
generator set. The motor-generator set has the c
I think a lot of the time audio-phools, if they will be honest with
themselves, are really trying to recreate the stereo (or even HiFi)
sounds of the 1960s because they have fond memories and like it better.
THAT I have no problem with whatsoever.
What gets annoying is when the phools try and
On 05/05/2021 07:44 PM, Donald via cctalk wrote:
Many thanks for all the info. I just wanted to make sure my recesses were
right.
I asked about MG because, in an audio forum, I see folks paying crazy money
for AC cords and power line conditioners. I thought a good MG would solve
many of th
Many thanks for all the info. I just wanted to make sure my recesses were
right.
I asked about MG because, in an audio forum, I see folks paying crazy money
for AC cords and power line conditioners. I thought a good MG would solve
many of the 'problems' they are trying to fix.
On 5/5/21 6:09 AM, Mark Linimon via cctalk wrote:
On Tue, May 04, 2021 at 10:07:28PM -0700, Chuck Guzis via cctech wrote:
"Power for the basic computer consists of one 250 kva, 400 Hz motor
generator set. The motor-generator set has the capability of providing
power for the CPU, MCS, I/O and th
Dr. Erik Baigar via cctalk wrote:
I've heard that. But why? It's not like the electronics we're
talking about actually runs on AC.
(a) Input filters often contain caps...
https://uk.tdk-lambda.com/content/faq/130796117766108286_FilterFAQ_how%20Image%201.jpg
With 50Hz or 60Hz they create a l
k
Note that VFDs are designed to run motors exclusively. They
approximate a sine wave with pulse width modulated 400 V pulses. DON'T
EVER try to run electronic gear with a VFD, at least without a massive
Yes, that is what I suggested; these filters are called "Sinus Filters"
in the field o
On Wed, May 5, 2021 at 12:27 AM Vincent Slyngstad via cctalk <
cctalk@classiccmp.org> wrote:
> On 5/5/2021 12:03 AM, Josh Dersch via cctalk wrote:
> > Until this point I've never had any peripherals for my negibus systems
> > (apart from teletypes), and it occurs to me that I have no idea if the
>
> On May 5, 2021, at 12:22 PM, Jon Elson wrote:
>
> On 05/05/2021 10:37 AM, Paul Koning via cctalk wrote:
>> Incidentally, a way to get three phase power at a frequency of your choice
>> is to use a "variable frequency drive". That's basically a high power solid
>> state inverter intended to
On 05/05/2021 10:37 AM, Paul Koning via cctalk wrote:
Incidentally, a way to get three phase power at a
frequency of your choice is to use a "variable frequency
drive". That's basically a high power solid state inverter
intended to drive three-phase motors with a chosen
frequency resulting in
On 05/05/2021 10:36 AM, Chuck Guzis via cctalk wrote:
As far as any "whine"--I vaguely recall hearing a
high-pitched whine if I put my ear close to the power
adjustment panel in a CDC Cyber--but it was barely audible.
The inverter whine on the 360/50 and /65 was completely
insane, and the 250
..not to forget, that the 400Hz equipment was readily available
from powering aircraft on the ground before the engines take
over. So although not cheap, they where cheaper than a custom
design at an arbitrary new frequency
On 05/05/2021 10:07 AM, Grant Taylor via cctalk wrote:
I have found the Motor Generator thread to be fascinating
and enlightening. But it has made many a reference to the
400 Hz or other frequency much higher than mains line
frequency. Despite the comments about the frequency, I'm
still conf
Hi,
Does anyone known which processor IBM used in the IBM 4701 — Branch
Controller (8″ floppy disc) ?
Regards Henk
On 05/05/2021 12:07 AM, Chuck Guzis via cctalk wrote:
Small S/360 systems were operated from standard AC distribution. I
don't know where the breakover was for IBM S/360; probably not for the
model 30, 40, or 75. The 195, I suspect did use an MG set.
"Real" 360's did not use MG sets. By rea
> Incidentally, a way to get three phase power at a frequency of your
> choice is to use a "variable frequency drive".
Please be careful with this! Have quite some experience in building
three phase inverters from such small boxes for my various avionics
projects.
(1) The normal ones rect
On 5/5/21 8:37 AM, Paul Koning via cctalk wrote:
> Incidentally, a way to get three phase power at a frequency of your
> choice is to use a "variable frequency drive". That's basically a
> high power solid state inverter intended to drive three-phase motors
> with a chosen frequency resulting in
On 5/4/2021 1:00 PM, Peter Dreisiger via cctalk wrote:
Firstly, apologies if my response doesn't show up nicely in this thread --- I
only receive the daily digests so I'm not sure how best to reply to a specific
post...
But on the subject of sourcing / making video cables with 3W3 connectors
On 5/5/21 8:37 AM, Paul Koning via cctalk wrote:
> Incidentally, a way to get three phase power at a frequency of your choice is
> to use a "variable frequency drive". That's basically a high power solid
> state inverter intended to drive three-phase motors with a chosen frequency
> resulting
..not to forget, that the 400Hz equipment was readily available
from powering aircraft on the ground before the engines take
over. So although not cheap, they where cheaper than a custom
design at an arbitrary new frequency
> On May 5, 2021, at 11:25 AM, Andrew Back via cctalk
> wrote:
>
> On 05/05/2021 16:07, Grant Taylor via cctalk wrote:
>
>> Were the higher frequencies used because it directly effected the amount
>> of time / duration in (fractions of) seconds between peaks of rectified
>> (but not yet smoo
On 5/5/21 5:18 AM, Paul Koning wrote:
> An earlier message commented on the whine from power converters. I
> don't know how common this practice was, but at the University of
> Illinois PLATO system which had a pair of 6500 systems, the
> motor-generator was located near the elevator machinery in
On 5/5/21 8:07 AM, Grant Taylor via cctalk wrote:
> I have found the Motor Generator thread to be fascinating and
> enlightening. But it has made many a reference to the 400 Hz or other
> frequency much higher than mains line frequency. Despite the comments
> about the frequency, I'm still confus
On 05/05/2021 16:07, Grant Taylor via cctalk wrote:
> Were the higher frequencies used because it directly effected the amount
> of time / duration in (fractions of) seconds between peaks of rectified
> (but not yet smoothed) power?
Haven't read the rest of the thread and so at the risk of being
> On May 5, 2021, at 11:07 AM, Grant Taylor via cctalk
> wrote:
>
> I have found the Motor Generator thread to be fascinating and enlightening.
> But it has made many a reference to the 400 Hz or other frequency much higher
> than mains line frequency. Despite the comments about the frequ
I have found the Motor Generator thread to be fascinating and
enlightening. But it has made many a reference to the 400 Hz or other
frequency much higher than mains line frequency. Despite the comments
about the frequency, I'm still confused as to why the higher than mains
frequency was used.
> -Original Message-
> From: cctalk On Behalf Of Mark Linimon via
> cctalk
> Sent: 05 May 2021 12:10
> To: Chuck Guzis ; General Discussion: On-Topic Posts
>
> Cc: Donald via cctalk
> Subject: Re: Motor generator
>
> On Tue, May 04, 2021 at 10:07:28PM -0700, Chuck Guzis via cctech wrote
> On May 5, 2021, at 1:07 AM, Chuck Guzis via cctalk
> wrote:
>
> Very large machines, certainly. There were "site preparation" documents
> that detail this.
>
> I can quote from the 1975 edition of the STAR-100 hardware manual on
> bitsavers (PDF page 25):
>
> "Power for the basic compute
On Tue, May 04, 2021 at 10:07:28PM -0700, Chuck Guzis via cctech wrote:
> "Power for the basic computer consists of one 250 kva, 400 Hz motor
> generator set. The motor-generator set has the capability of providing
> power for the CPU, MCS, I/O and the MCU. The optional memory requires
> the addit
On 5/5/2021 12:27 AM, Vincent Slyngstad via cctalk wrote:
On 5/5/2021 12:03 AM, Josh Dersch via cctalk wrote:
Until this point I've never had any peripherals for my negibus systems
(apart from teletypes), and it occurs to me that I have no idea if
the bus
needs to be terminated (and if so,
On 5/5/2021 12:03 AM, Josh Dersch via cctalk wrote:
Can anyone with negibus experience point me in the right direction?
As you and Ethan helped me with on FB about my 8/I, I don't know which
bus I had. And worse it
went to a second rack with about 10 of the expansion racks built out
with de
> -Original Message-
> From: Tony Duell [mailto:ard.p850...@gmail.com]
>
> On Wed, May 5, 2021 at 8:12 AM Paul Birkel wrote:
> >
> > > -Original Message-
> > > From: Tony Duell [mailto:ard.p850...@gmail.com]
> > >
> > > > On Tue, May 4, 2021 at 10:33 AM Paul Birkel via cctalk
> >
On Wed, May 5, 2021 at 8:12 AM Paul Birkel wrote:
>
> > -Original Message-
> > From: Tony Duell [mailto:ard.p850...@gmail.com]
> >
> > > On Tue, May 4, 2021 at 10:33 AM Paul Birkel via cctalk
> > > wrote:
> > >
> > > I'm currently reverse-engineering an AMPEX keyboard that uses capacitiv
On 5/5/2021 12:03 AM, Josh Dersch via cctalk wrote:
Until this point I've never had any peripherals for my negibus systems
(apart from teletypes), and it occurs to me that I have no idea if the bus
needs to be terminated (and if so, with what). There are 6 slots in the
RF08 backplane (D01-D06) f
> -Original Message-
> From: Tony Duell [mailto:ard.p850...@gmail.com]
>
> > On Tue, May 4, 2021 at 10:33 AM Paul Birkel via cctalk
> > wrote:
> >
> > I'm currently reverse-engineering an AMPEX keyboard that uses capacitive key
> > switches. The basic design employs a GI encoder coupled
Hey all --
I cabled up the RF08 to my 8/I this evening and it's showing some very
faint signs of life -- a DIML instruction appears to do the right thing.
That's about it.
Until this point I've never had any peripherals for my negibus systems
(apart from teletypes), and it occurs to me that I hav
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