[evlatests] UPS outages at VLA

[Eugene Cole]

FYI, please anticipate accordingly.

---------- Forwarded message ----------
Date: Fri, 27 Apr 2007 14:59:06 -0600 (MDT)
From: Bob Broilo <bbroilo at nrao.edu>
To: VLA Operators <vlaops at nrao.edu>, Dick Sramek <dsramek at nrao.edu>,
    Pat Van Buskirk <pvanbusk at nrao.edu>, Peggy Perley <pperley at nrao.edu>,
    James Sullivan <jsulliva at nrao.edu>, Marie Glendenning 
<mglenden at nrao.edu>
Subject: New UPS installation: scheduled outages

Please feel free to forward this.  If you have questions or comments,
email me or call at 7404.  We will do everything we safely can to minimize
the outages.

Brief:

We need to shut down UPS loads in the VLA Control Building from 7:30AM
to 4:30PM on the following days: May 8-9 and 23-24.  These loads
include the correlator, operations area, modcomps, ALMA racks,
servers, internet, etc.  The fire alarm will give trouble indication
due to AC input failure but should continue to function on internal
battery backup.  The phone system should also continue to function.

Detail:

The expected EVLA loads are 190kVA at times during the transition and
160kVA for EVLA.  The existing CB UPS was installed for the Voyager
flyby.  It is a 150kVA unit.  Although it has survived beyond it's
expected lifetime admirably, it is starting to fail and parts are
getting extremely expensive and hard to find.

We purchased a new 225kVA unit to replace it.  This new unit will also
assume the new loads.

To install the new unit, we must interrupt the power to the loads that
it feeds.  Fortunately, the first step in the installation process
rewires the UPS to a full external bypass system.  This means that the
UPS can be completely isolated electrically from the loads so that the
load does not have to be disconnected for future work.  Unfortunately,
this means that these loads will be unprotected from sags and
interruptions from the utitily during the swap.

Thanks,
Bob.

Bob Broilo
505-835-7404
bbroilo at nrao.edu
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