Re: UPS ( APC vs MGE )
From: Imitheos (imitheos_at_hotmail.com)
Date: Fri, 22 Oct 2004 01:50:56 +0300
> Now lets put some numbers to the speculation. The typically
> destructive surge occurs about once every eight years. So
> what did that APC UPS protect during but a few years? Because
> a destructive surge has not yet occurred, then that proves the
> APC Back-UPS is an effective protector?
Here (In Greece) in winter there are many lightning strikes, but
i understand what you said "Direct lightning strikes occur often
without any damage."
I guess when someone uses a UPS has the false impression that
he is protected.
> UPS typically connects computer directly to AC mains when
> not in battery backup mode. So where is the UPS protection?
> Furthermore, transients must bypass computer power supply to
> get into ICs. That would be via the safety ground wire.
> Safety ground wire also completely bypasses UPS. So again,
> the UPS provides no effective protection - having been
> bypassed by a safety ground wire.
Line-Interactive UPSes run the computer out of the AC mains but
they supposedly have a microprocessor which controls,filters
(cuts-off spikes,noises) and regulates the output.
> No sense wasting big bucks on a UPS only for surge
> protection. Its function is data protection from blackouts and
> brownouts. How much is that UPS to only protect one computer?
> $70+? Effective 'whole house' protector costs about $1 per
> protected appliance.
> UPS does claim to provide normal mode protection. But a
> properly sized 'whole house' protector also protects from that
> one type of transient; and does not self destruct.
> Unfortunately, MOV joule rating for a plug-in UPS is often too
> undersized to be effective.
The MGE Ellipse Premium claims 525 Joules of surge suppression
(in its manual it mention also a 140 Joules line filtering),so
if i understood what you were saying in the other posts, its
effective surge protection is at 525/3=175 Joules.
(The standards it conforms to are the following:
EN 50091-1-1, EN 60950(RD), IEC 60950, TÜV GS-Mark (DIN model)
EN 50091-2, EN 50022/B, IEC 62040-2, IEC 61000-3-2, IEC 61000-3-3)
I don't think i can find the "Intermatic EG240RC" here in Greece,so
i will check for "Siemens QSA2020."
Some cities here(especially islands) suffer from frequent
flunctuantions in voltage. The voltage the power company provides,
it is not good.A friend of mine lives in such a area and tells me
the UPS saved him. Do you recommend this kind of UPSes
(Line interactive) just for the line filtering and regulating and not
for serious surge protection ? Or as you mentioned before you
think that the pc PSU can withstand these flunctuations and
correct them itself ?
I have read carefully(i believe) what you have said here and in
the other two discussions and have learned many things i ignored
till now. Thank you very much for your time, and i hope i won't
bother you much more.