1 Jun
1998
1 Jun
'98
8:23 a.m.
On Mon, 01 Jun 1998 14:49:39 rigdonj(a)intellistar.net remarked:
Oddly enough a lot of the HP stuff is spec'd to
run on 50 to
440 Hz. I'm not sure why unless it's to allow it to also be used
in aircraft but that doesn't seem likely.
Shipboard applications are frequently run at 440 Hz as well as
aircraft; it's quite common in military environments as it keeps the
transformers small. Actually, I believe it's 400 Hz, not 440, but
whats a few ticks between friends?
On a similar note, ferroresonant transformers can do some very
bizarre things when offered a mains frequency they weren't designed
for. DG's Eclipse S/230 uses a single resonant transformer, rectifiers,
and filter caps for its power supply and little else. The specifications
call for a mains frequency deviation of under 1/2 Hz in either
direction. However, if the frequency is good, the regulation that
the supply gives is quite remarkable.
______________________________________________________________________
| | |
| Carl Richard Friend (UNIX Sysadmin) | West Boylston |
| Minicomputer Collector / Enthusiast | Massachusetts, USA |
| mailto:carl.friend@stoneweb.com | |
| http://www.ultranet.com/~engelbrt/carl/museum/ | ICBM: N42:21 W71:46 |
|________________________________________________|_____________________|
1 Jun
1 Jun
10:41 a.m.
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4:33 p.m.
On Mon, 1 Jun 1998, Tony Duell wrote:
Tony, the Miniscribe 84nn series used a stepping motor and a rack and pinion
as a head positioner, also. There are a few others, but the make/model
do not come to mind.
- don
donm(a)cts.com
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Don Maslin - Keeper of the Dina-SIG CP/M System Disk Archives
Chairman, Dina-SIG of the San Diego Computer Society
Clinging tenaciously to the trailing edge of technology.
Sysop - Elephant's Graveyard (CP/M) - 619-454-8412
*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*
see old system support at http://www.psyber.com/~tcj
visit the "Unofficial" CP/M Web site at http://cdl.uta.edu/cpm
with Mirror at http://www.mathcs.emory.edu/~cfs/cpm
On a
similar note, ferroresonant transformers can do some very
bizarre things when offered a mains frequency they weren't designed
for. DG's Eclipse S/230 uses a single resonant transformer, rectifiers,
and filter caps for its power supply and little else. The specifications
call for a mains frequency deviation of under 1/2 Hz in either
direction. However, if the frequency is good, the regulation that
the supply gives is quite remarkable.
Well, late versions of the power supply for the DRI/Diablo Model 30 disk
drives (AKA DEC RK02 and RK03) used a ferroresonant transformer. It
provided the +15V and -15V lines (the former was regulated conventionally
for the +5V line, I think). There was no other regulation on these lines,
which supplied most of the analogue circuitry and the motors in these
drives. Only drive I ever saw that used a DC permanent magnet motor and a
rack and pinion drive as the head positioner... | Carl Richard
Friend (UNIX Sysadmin) | West Boylston |
-tony
2 Jun
2 Jun
5:48 a.m.
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1 Jun
1 Jun
3:06 p.m.
New subject: What is it called when the 60hz line power becomes something else?
At 04:23 PM 01-06-98 -0400, Carl R. Friend wrote:
Shipboard applications are frequently run at 440 Hz
as well as
aircraft; it's quite common in military environments as it keeps the
transformers small. Actually, I believe it's 400 Hz, not 440, but
whats a few ticks between friends?
As the topic drifts away from computers, I've just got to ask how they
isolate equipment running at 440Hz (or 400Hz). 50Hz hum is bad enough, but
440Hz is rather
noticeable. Of course, for those of us with perfect pitch, we'd notice line
frequency changes of a few 10s of Hz. Perhaps I should volunteer for
aircraft line frequency monitor :-)
Huw Davies | e-mail: Huw.Davies(a)latrobe.edu.au
Information Technology Services | Phone: +61 3 9479 1550 Fax: +61 3 9479
1999
La Trobe University | "If God had wanted soccer played in the
Melbourne Australia 3083 | air, the sky would be painted green"
2 Jun
2 Jun
1:41 a.m.
Carl R. Friend wrote:
On Mon, 01 Jun 1998 14:49:39
rigdonj(a)intellistar.net remarked:
It's generally 400 (plus or minus 50) hz for aircraft and associated
equipment (missiles for instance). Our test equipment racks for Air Launched
Cruise Missiles had a HP 1000 computer tied to an IEEE 488 interface and all
of that ran from a motor-generator that took 3 phase 220 volt @ 60hz to
power an electric motor that turned a generator similar to an aircraft's
engine driven generator.
The biggest advantage of the higher cycle rate is smaller packages and
cooler running.
Locomotives and (as you stated) larger water craft also use 400hz equipment.
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Oddly enough a lot of the HP stuff is
spec'd to run on 50 to
440 Hz. I'm not sure why unless it's to allow it to also be used
in aircraft but that doesn't seem likely.
Shipboard applications are frequently run at 440 Hz as well as
aircraft; it's quite common in military environments as it keeps the
transformers small. Actually, I believe it's 400 Hz, not 440, but
whats a few ticks between friends? 
2:11 a.m.
It's generally 400 (plus or minus 50) hz for
aircraft and associated
equipment (missiles for instance). Our test equipment racks for Air Launched
Cruise Missiles had a HP 1000 computer tied to an IEEE 488 interface and all
of that ran from a motor-generator that took 3 phase 220 volt @ 60hz to
power an electric motor that turned a generator similar to an aircraft's
engine driven generator.
Quite a bit of military equipment actually is rated to 2400 Hz. The reason
for this is that some of the pre-1940 aircraft (namely U.S.Navy) used 800
Hz power. There were also probably a few applications that went a bit
further in line frequency, but I am not aware of them. Anyway, an amazing
amount of this pre-war "junk" stayed in service into the 1970s.
If anyone wants a BIG 400Hz convertor from an IBM 3090 installation, there
is one in a junkyard in Illinois. It looks to be in the 1500 pound
category.
Locomotives [...] also use 400hz equipment.
Maybe the new ones, but the old ones used 25 Hz.
William Donzelli
william(a)ans.net
9700
days inactive
9701
days old
6 comments
6 participants
participants (6)
-
ard＠p850ug1.demon.co.uk -
crf＠stoneweb.com -
donm＠cts.com -
H.Davies＠latrobe.edu.au -
rhblake＠bbtel.com -
william＠ans.net