|
|
| Author |
Message |
tnt
|
|
Uninterrupible Power Systems
| 
May 7 03:38 UTC 1992 |
Are there any places in the A2 area that sell decent UPSs, such as those
made by Best or American Power Conversion?
I'm in the market for a 700VA - 1KVA on-line UPS.
Also, can anyone remember which magazine recently (within the past year)
had a good cover story about UPSs?
|
| 26 responses total. |
mistik
|
|
response 1 of 26:
|
May 7 04:33 UTC 1992 |
I don't know about a store, but if you decide which one, most people here
would be able to get you one with little markup. But you wouldn't have the
nice feature of taking it back to the store though.
|
mju
|
|
response 2 of 26:
|
May 8 22:00 UTC 1992 |
Dominant Systems sells UPSes. I beleive that we deal mostly in
the Elgar line, but I can recall seeing some Best UPSes come through
as well. Give us a call on Monday if you're interested (971-1210).
|
rcurl
|
|
response 3 of 26:
|
Feb 13 18:16 UTC 1993 |
What did you finally do, Tim? I've often thought of getting a UPS, but
have instead just shut down when the western sky gets murky and flashy.
So far, I've been lucky.
|
danr
|
|
response 4 of 26:
|
Feb 13 23:53 UTC 1993 |
I bought an Emerson Accupower from the one and only Dave Parks, and
have been quite happy with it. He gave me a pretty good deal, and
it's saved my butt a couple of times.
|
rcurl
|
|
response 5 of 26:
|
Feb 14 06:59 UTC 1993 |
I see a APC 250 VA UPS for $110 (new). Is that a good model and a good
price?
|
mju
|
|
response 6 of 26:
|
Feb 14 08:00 UTC 1993 |
APC UPSes are fairly nice; DSC recently got two APC Smart-UPS 400VA
UPSes for our network servers. Is the one you're talking about a
Smart-UPS or a Back-UPS? The Smart-UPS has various monitoring functions
(usable with the companion PowerChute software) that can tell you
the high and low line voltage, current UPS load, internal UPS temperature,
and so forth. The Back-UPS doesn't have these extensive functions; it
can just tell you whether the UPS is on battery on not, and whether the
battery is about to run out.
|
rcurl
|
|
response 7 of 26:
|
Feb 14 20:37 UTC 1993 |
The price I quoted was for a Back-UPS. The same source sells the Smart-UPS
400 for $333. Do those extra features really help much, considering that
the thing will be ignored until the "moment of truth", and then one doesn't
care, except to hope it holds out. (Or is it the RS232 monitoring feature
you wanted?)
|
steve
|
|
response 8 of 26:
|
Feb 14 20:41 UTC 1993 |
I'm drooling over the rs-232 capability right now. I'd love to
have one of those for about a week, to watch Grex's power.
|
rcurl
|
|
response 9 of 26:
|
Feb 14 20:49 UTC 1993 |
Well, Marc has two, and could probably spare one ;-).
|
mju
|
|
response 10 of 26:
|
Feb 16 00:24 UTC 1993 |
(Uh, "Marc" doesn't have any. Dominant Systems, which is emphatically *not*
the same as "Marc", has two. But I don't think they'd be too amenable to me
borrowing our company fileserver's backup power for a week.)
Both the Smart-UPS and the Back-UPS have RS-232 monitoring. It's just that
the Smart-UPS provides more extensive information than the Back-UPS does.
As for whether or not it's worth anything -- I'd certainly like to know that
my UPS was being run at 110% of maximum load, or that the battery was low,
BEFORE my power failed rather than after.
|
rcurl
|
|
response 11 of 26:
|
Feb 16 02:47 UTC 1993 |
Hmmm I find it strange that the catalog I have listing the Back-UPS 250
makes no mention of RS232 monitoring: seems it would be a selling point.
But then, they don't list that feature for the Smart-UPS 600 either! Only
the S-U 400. I guess its just bad catalog writing. Say, Marc, wouldn't
those two fileservers run off one S-U for a few weeks?
|
mju
|
|
response 12 of 26:
|
Feb 16 04:26 UTC 1993 |
Maybe. But the Smart-UPS auto-shutdown puts the UPS to sleep after the
system shuts down; this causes problems if more than one system is
hooked to the UPS.
|
mkoch
|
|
response 13 of 26:
|
May 18 21:46 UTC 1994 |
Humm, yap, PC Magazine had a review on UPS'es, since I can remember it it
cannot be long ago.
|
rcurl
|
|
response 14 of 26:
|
May 19 05:30 UTC 1994 |
Well! A chance to follow-up on #11! I got two Back-UPS 250 in 8/93,
when the vendor was having a sale, and they've been sitting there
improving my state of mind since, though I have not yet had a power
outage while operating. I guess I should test them again, soon.
|
n8nxf
|
|
response 15 of 26:
|
May 19 16:28 UTC 1994 |
By this time the batteries have sulfated and they will have no capacity
when an outage does come along ;-) Yea, better test them.
|
rcurl
|
|
response 16 of 26:
|
May 19 17:47 UTC 1994 |
Gee, such encouragement. Well, *one* of them is OK. The SE is still
up, and the UPS is beeping.
|
rcurl
|
|
response 17 of 26:
|
Oct 3 06:24 UTC 1996 |
The SE gave up the ghost, and I've upgraded to a PowerMac, and now
need a UPS upgrade. Investigating this has led to some curiosities and
questions. The firsts is, how much power?
The label on the bottom of the PowerMac says 100-120 V., 7.0 A.
The PowerMac manual says the power requirements are 215 watts max continuous
and 300 watts peak.
I measured the current to the CPU with the CD-ROM running, and it was less
than 1 ampere (my clip-on ammeter's lowest scale is 5 A) - less than 100W.
Well, with three boards added, and the floppy running, it might draw 200W.
So, maybe I need a 200 watt UPS.
But wait! UPSes are rated in VA, not watts. The APC Owner's Manual says
"If load ratings are given in Watts (W), convert to an estimate of power
requirements in VA by multiplying the value in Watts by 1.4. Hmmm...well,
if the current lagged the voltage by 45 degrees, the power factor would
be 1/SQRT(2), but what is behind this "universal" prescription? Is it just
so they can list the Back-UPS 400 with a bigger number, rather than its
real 290 watt capacity?
It looks like if I "load" the PowerMac with all the auxilary boards it
will take, I need 215 watts there, and 90 watts for the monitor (that
checked out OK with the ammeter), for 305 watts, or 430 VA. Is that what
you would use? (A 400 VA and a 450 VA UPS are available from APC).
|
n8nxf
|
|
response 18 of 26:
|
Oct 3 12:52 UTC 1996 |
That's most likely the way it is. Big numbers sell. 250 watt power
supplies in computers that consume 60 watts, 225 MHz CPUs, etc.
Switching supplies are capacitive loads so I guess it makes sense that
you need a bigger VA rating on the UPS to accommodate the leading
current.
|
rcurl
|
|
response 19 of 26:
|
Oct 3 15:52 UTC 1996 |
Capacitive? I always think underloaded power supplies are inductive,
because of the Xformer. Guess I have to learn how a switching supply
works.
In regard to Watts and VA - I'd still like to know if there is any real
technical reason for APC asserting that magic number "1.4" (=VA/W)? And
whether it is related to a power factor at 45 degrees and, if so, why that
value? Not all users of APC UPSes are electrical dummies that they want to
fool with fudged numbers - there must be a rationale buried somewhere.
|
n8nxf
|
|
response 20 of 26:
|
Oct 4 14:10 UTC 1996 |
The only thing I use 1.4 for is to get a rough idea of what value DC
I'm going to get when I rectify a sine wave with a full wave bridge.
Swithers are capacitive loads. Basically they take whatever is on the
line, rectify it, filter the result with some big caps, and chop the
resulting DC through a ferrite core transformer. Some HF filtering is
put on the line side to keep the HF chop from getting out on the line.
|
rcurl
|
|
response 21 of 26:
|
Dec 6 18:32 UTC 1996 |
I can get a 450 VA Back-UPS (APC) for $184.25, or a BC Internet UPS
(TrippLite) for $150. The TrippLite has phone line surge/spike protection
jacks. Is there anything I should know about the difference between APC
and TrippLite technology? The catalog says the Back-UPS has user
replaceable batteries, but is silent on whether the TrippLite does or not
(though, there must be a way in.... ;->).
|
n8nxf
|
|
response 22 of 26:
|
Dec 6 21:16 UTC 1996 |
Back in the days when I did some inverter studies for medical applications,
TrippLite was one to stay away from. Dirty output, poor regulation, frequancy
instability and marginal construction. However, things have changed a *lot*
in the inverter industry in the last ten years! Chips that handle most of
these chores are common and I suspect that TripLite will be OK for you
application. (If they are still around, Power Var was superb and very
inexpensive. We still have one here and it's been flawless. It preformed
better than units costing ten times more!
|
alan
|
|
response 23 of 26:
|
Jan 12 02:54 UTC 1997 |
Tripplite makes the 'isobar' surge protectors and line filters. I just had
oneself destruct taking a hit for my computer. I called them in Chicago and the
sent me
|
rcurl
|
|
response 24 of 26:
|
Jan 12 07:09 UTC 1997 |
I ordered the Tripplite BC Internet from Lyben Computers, who were having a
sale, but they were sold out and back ordred them. Hmmm...that was over
a month ago - better check up on it.
|