On Feb 10, 4:56 pm, Dudley Henriques <dhenriq....RemoveThis@rcn.com> wrote:
> I just want to thank everyone who answered in this thread. I read all of
> it and appreciate your time. I learned a lot from your input.
How many responders learned by designing stuff and fixing things by
literally replacing semiconductors? Posted along side some good ideas
are numerous popular myths.
First, low voltage does not harm properly designed electronics.
Just another normal electrical problem made completely irrelevant by
functions inside the power supply. Low voltage may cause data loss. A
UPS provides data protection (as others have noted); not hardware
protection.
Read numeric specs for a UPS. Where are numeric claims for hardware
protection? It does not. Why does the manufacturer not even claim
what others have posted here? Worse, some of the 'dirtiest'
electricity seen by a computer will come from a 'computer grade' UPS
when in battery backup mode. For example this 120 volts UPS outputs
two 200 volts square waves (not sine waves) with a 270 volts spike
between those square waves. A computer grade UPS outputs electricity
so 'dirty' as to even harm some small electric motors. Computer grade
because the same electricity is not harmful to computers. Since
computer power supplies are so robust, then that 'dirty' UPS power is
'computer grade' power. How many others learned this stuff by even
confirming those numbers with an oscilloscope? How many posters read
those manufacturer specs?
Second, why would a UPS protect Ethernet ports? Did you know
ethernet ports must withstand thousands of volts without damage?
Again, read those specs. Where did a destructive thousands of volts
come from? At least one recommended a protector located on circuit
breaker panels. But a protector is not protection. A protector is
only a connecting device to protection. When the protectors makes
that 'less than 10 foot' connection to earth ground, then that
thousands of volts need not enter the building to find earth ground,
destructively, via those ethernet ports. Earth ground is why the
electic panel protector does something useful.
What provides electrical and electronic protection? Even your
dishwasher requires such protection. Protection is provided by earth
ground. Thousands of volts that sees earth ground where those volts
enters the building need not find earth ground, destructively, via
appliances.
Power supplies are so robust; contain functions that make electrical
anomalies irrelevant. Both numbers from Intel specifications and from
from more responsible power supply vendors put those numbers at
thousands of volts for a 120 volt power supply. Where does a multi-
thousand volt spike come from to overwhelm protection inside
appliances, a computer, and those ethernet ports? If this voltage
spike connects to earth ground where each wire enters a building, then
protection inside appliances (including dish washer) will not be
overwhelmed.
Third - citations from professionals. Electrical Engineering Times
defines electrical appliance protection in two front page articles on
1 Oct and 8 Oct 2007 entitled "Protecting Electrical Devices from
Lightning Transients" at:
http://www.planetanalog.com/showArticle.jhtml?articleID=201807127
http://www.planetanalog.com/showArticle.jhtml?articleID=201807830
Where do those articles discuss a UPS? The article is not discussing
myths. It discusses protection as has been well understood even 100
years ago. Protection is defined by earth ground. A protector with
that short (less than 10 foot) connection to earth has THE only
required component in every protection solution: earth ground.
Many forget to see protection as a 'system'. A 'magic box' (ie
UPS), instead, will provide a solution? Hardly. How did thousands of
volts enter a building to damage so many ethernet ports? Did anyone
ask that question, or just speculate? Somehow that silly little one
inch part will stop what three miles of sky could not? That is the
myth.
Reality: your telco's $multi-million computer, connected to overhead
wires all over town, may suffer 100 surges during every thunderstorm.
And no damage. Why? Telcos do what is posted here to not have
damage. A superior solution that also costs tens or maybe a hundred
times less money. Every incoming wire must connect, short, to the same
earthing electrode. Both front page EE Times articles make that
point. A direct wire connection or that 'less than 10 foot'
connection is via a protector. The protector is not protection. The
effective protector is simply a connecting device so that thousand of
volts will not enter the building to damage, for example, ethernet
ports.
Finally, some power supplies sold to clone computer assemblers are
missing essential functions. That computer power supply must
withstand a thousand volts without damage. Does that one supply
contain those internal functions? How does a power supply sell for
$25 and $40 retail? Forget some essential functions when selling to
people who assemble computers and do not even know how electricity
works. So we fix a $25 missing function with a $100+ UPS? A UPS that
does not even claim to solve the problem? A UPS that has no 'less
than 10 foot' connection to earth ground?
Every wire entering the building must connect to single point earth
ground as demonstrated by this application note from an industry
professional:
http://www.erico.com/public/library/fep/technotes/tncr002.pdf
Every wire in every cable (including underground cables - see that
figure) makes a short connection to single point earth ground where
the cable enters a building. A 'whole house' protector in a breaker
box can do just that. Telco already installs an effective protector
for free (did others know that telco installed protector exists?). TV
(coax) cable drops down to make an earthing connection before entering
the building. Even grounded to a water faucet is not sufficient..
Where does that UPS provide hardware protection claims? Where are the
numbers? A UPS to protect ethernet ports is not found in engineering
facts; only found in popular myths.
How does your telco, commercial broadcasting stations, airports, 911
emergency response centers, etc all suffer direct lightning strikes
and no damage? This post even includes professional citations
including two front page articles from EE Times. This post from one
who learned why failures occur by tracing source of the damage AND by
literally replacing semiconductors. Posted here is contrary to a
majority of other posts. But how many others asked damning questions
such as why? How many even cited a single manufacturer specification?
How many explained how protection works? A UPS does not even claim to
protect hardware. Low voltage does not harm electronics despite
popular myth. How many know a UPS in battery backup mode outputs
electricity so dirty as to even damage some small electric motors?
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