How does one figure the number of KVA needed for a UPS and how does this
relate to the length of time
the system will run on the battery power provided from the UPS?
KVA is apparently found by the equation Volts x amps, so for example,
running a system that consumed
30 amps at 208 Volts means I need a minimum of 6240 KVA.
For an Alpha box, how does one figure the total amps consumed. For example,
suppose the Systems and Options catalog states that the system consumes 30A,
with a peak of 50A. Does this usually include all the disks and storage shelves
that can be held inside the box?
Or, do I have to add up the power consumed by each disk drives, plus the
storageworks shelves themselves and their power supplies?
Perhaps to choose an absurd example (or one with wishful thinking), an 8400
system according to the Systems and Options Catalog is rated at the 30 / 50
A mentioned above. If I had one with say, 10 9-GB disk drives and one
storage box, will that all still consume the 30 A mentioned in the SOC?
Second, what is the relationship between KVA and the length of time a
sysytem will stay up on it's UPS. Again, the SOC states that a 15 KVA UPS
will run an 8400 system at full load for 10 minutes.
Simply how do I figure out how many KVA I need for what length of time when
running under battery?
There must be an algoritm or an heuristic to figure this out. It's probably
clear by know I'm not an EE.
I look forward to summarizing this one.
Thanks and regards,
Bruce
+--------------------------------------+
Bruce B. Platt, Ph.D.
Comport Consulting Corporation
78 Orchard Street, Ramsey, NJ 07446
Phone: 201-236-0505 Fax: 201-236-1335
bbp_at_comport.com, bruce_at_ bruce.platt_at_
Received on Wed Sep 09 1998 - 21:49:35 NZST