🚀 go-pugleaf

In article <1992Apr7.141549.6503@cerritos.edu>, tanner@cerritos.edu writes:
> systems, so if anybody has done this research, I'd like a rough dollar figure
> for a data center UPS.
> 
> Can this be done with battery systems?  Or are motor-generators necessary?
> 

We have three 60KVA DEC/EPE Technologies HA32 UPS Systems in place here.  One
of them powers:

2 VAX 6000-520s w/5 BIs apiece
2 RA92s
1 SA705 Storage Array with 4 RA71s installed
2 MicroVAX 3s (H9642 cab) with Internal RD53s
7 RA81s
4 TU81Es
and other assorted odds and ends.

This one UPS is currently running at about 37% of capacity. With the standard
duration batteries (rated at 15 minutes at rated power output) this
configuration provides about 1 hour of power until battery depletion causes an
UPS shutdown.  In the event of a brown out the UPS will work considerably
longer since input power will be used as long as it is in excess of the 325 V
battery exhaustion level (assuming 480V input power). This configuration cost
us  about $70,000 with the usual 21% government discount and without power
cables ($200-$500 a piece, if you buy from DEC, any electrician can make
equivalents for a third of that).  You might be able to reduce the costs by
going to a lower UPS output rating and buying long duration batteries.  We
wanted the higher output rating to provide for long term growth capability.

We do not have motor-generators in front of the UPS here.  We are powered from
480V commercial power and our power here is very noisy because the base
power system is old and lacks sufficient capacity (a major upgrade is now under
way).  I don't think that motor generators should be required in addition to an
UPS.  But we have had considerable problems with the control circuitry of the
HA32s, so you might want to consider it, depending on your power quality and
operational environment.  I would recommend the REMS/EMS hardware/software
package with the UPS if you run unattended for any length of time longer than
your battery life.  See the Horror Story below for reasoning.

HA32 HORROR STORY

During a recent basewide power outage all three of our UPS reached battery
exhaustion and shut down.  ( When the HA32 does a shutdown, it leaves itself in
Static Bypass mode so that raw commercial power is passed straight through the
UPS to your equipment, especially all those nice spikes, sags, and other kinds
of transients that occur as the power net is reenergizing. ) As a result of the
shutdown and startup, all three of our HA32s were disabled, one with blown
fuses, one with burned control circuity, and one with a shorted inverter leg. 
Cost to repair all three, around $10,000 and still climbing. By the way, these
UPS are 2 years old.  We have had previous problems with blown fuses and burned
control circuitry on at least two occasions. Consequently, we had installed DEC
transient voltage surge suppressors (TVSSs, ~$700) ahead of the UPS because DEC
told us that they would eliminate that problem.  They obviously did not. 

What's more we have approximately 30 VAXstations, and numerous PCs, and other
equipment  plugged either directly into the wall or into low cost surge
suppressors.  In addition the UPS passed the same raw commercial power that
blew them all out of the water straight through to all of our "protected
equipment". Not one of these pieces of equipment so much as tripped its
circuit breaker or blew a fuse.  Makes my blood pressure rise just thinking
about it again.

All the problems that we have had with the UPS have occurred when our systems
were running unnattended overnight or on weekends, power was lost for an
extended period, and the UPS reached battery exhaustion and tripped themselves
into static bypass.  Otherwise the systems have performed well.  Consequently,
we have purchased REMS/EMS to ensure that the systems get shutdown when the
power goes out overnight or on a weekend and that we don't reach battery
exhaustion.  We have also decided to pay EPE $10,000 a/year for a comprehensive
maintenance contract on all three UPS and their batteries (this includes
battery replacement when required).

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Gary S. Martin                !  (805)277-4509  DSN 527-4509
6510th Test Wing/TSWS         !  Martin@Edwards-TEMS.af.mil
Edwards AFB, CA 93523-5000    ! 
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