[time-nuts] Oscilloquartz BVA has been sold. Thank you all who expressed an interest.

[Bill Notfaded]

Where I work on a smaller isolated network we have an APC that takes up one
full rack.  Most of the rack is modular batteries that are 6 batteries in
19" x 4U high... A bunch of rows of these in one rack with a few units that
are the control and monitoring system.  That one rack can support 6 rows of
racks of equipment 5 19" racks wide.  That one APC rack can run all the
computers, NAS, blade centers, etc. for about an hour.  Some of the racks
are 110AC some are 208AC depending on circuit it's on.  It seems like I
could get one of the bottom of the rack APC units (really heavy) that are I
think 4U high.  The batteries usually last longer depending on the load.
Our big unit tells you right on the front how long in minutes it will last
based on the current load.

Are you saying if the load is small it'll still run out pretty quickly?  I
was thinking just plug a few things in:
BVA power supply, HP 105B, some GPS/GNSSDO's and the HP5065A.  I don't even
think there's any reason to plug a Cesium into it.  If a Cesium in storage
mode is off for a while who cares right?  I have a few older Efratom Rb too
FRK-L and a couple M-100.  Would those benefit from staying on?  I have a
few newer Rb but they would just run until Rubidium ran out right like SRS
PRS-10 and L-Pro's?  I've heard the older Rb can be ran all the time
because they have much more Rubidium in them.  Up to this point I usually
run them for a couple days to stabilize them before using them.  I'm not
100% sure if leaving them on all the time is of much benefit?  I know Ed
told me he leaves his 5065 on all the time so I'm planning the same thing
right now also mines recently put back together and as it runs it's getting
better and better right now.

I really like these older Rb units with larger physics packages.

Best Regards,

Bill

On Sat, Sep 26, 2020, 9:16 AM Mark Spencer <mark at alignedsolutions.com>
wrote:

> A few decades ago I  worked with some quite large Telecom gear that ran
> from 208 volt AC.    The equipment had its own internal 48 volt supplies
> and short term battery back up system (basically so the redundant CPU units
> could gracefully shut down in the event of a power failure.)   The
> manufacturer also sold similar systems that ran from customer supplied 48
> volts but many enterprise customers who already had large UPS systems and
> back up generators preferred the versions that ran from 208 volt AC.
>
> Some smaller office phone systems back in the early 1990's also featured
> large external battery packs to get multi hour run times.   The vendors
> would typically send technicians out to peridoically check the battery
> systems.   The few that I was able to examine were typically made up from 2
> volt sealed lead acid cells.   The used cells used to be some what
> available to hobbyists as the tended to get replaced before they failed.
>
> Yes some large UPS systems don't work very well at supplying low levels of
> power for long the periods.   During a multi hour maintenance shut down at
> work a few decades ago we had one device that we hoped to keep running
> (essentially a small digital voice play back unit that played phone system
> messages, ie. "The number you have reached is not in service.")  It drew
> well under 100 watts and was the only load at the time for a large UPS
> system with multiple battery banks which stopped running after a few hours
> and I had to re record the messages.   None of us were very surprised.
>
>
> Mark Spencer
> mark at alignedsolutions.com
> 604 762 4099
>
> > On Sep 26, 2020, at 12:33 AM, Hal Murray <hmurray at megapathdsl.net>
> wrote:
> >
> >
> >>> Can't I just use a high quality APC backup power system
> >>> like we use to power racks of gear in our Telco and compute closets?
> >
> >> Very few UPS's are good at long-run applications, they are typically
> built to
> >> run a heavy load for minutes, not a tiny load for hours or even days on
> end.
> >
> > That matches my expectations, but somebody might expect their telco gear
> to
> > stay up longer than the few minutes it takes to cleanly shut down a
> computer.
> >
> > Is there a branch of UPS gear aimed at telco rather than computers?
> That is
> > good efficiency at low power and long time rather than high power for
> short
> > time.
> >
> > Does all telco gear that is expected to run off UPS take 48V?
> >
> > Is there a market in small 48V supplies with UPS option for the telco
> market?
> > You would have to build a 48V to 24V converter rather than the whole
> thing.
> > You can probably get a brick for that.
> >
> >
> >
> > --
> > These are my opinions.  I hate spam.
> >
> >
> >
> >
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