As a result of recent events, I have two surge protectors that no longer
function without putting out loud noises on HF. I found that the $5
surge protector that my Yaesu was plugged in to was making a loud
whistling noise which was covered up by the louder warbling noise being
made by the Belkin I had my computer plugged into. So I decided to break
them open to see what was inside. The easiest was Old El Cheapo, held
together with screws. Inside was a length of wire, a switch and ONE disc
capacitor wired into six plugs. IMO that's little better than a plain
old power strip. The Belkin had no screws, so it took a little longer to
crack. The results: a switch, two LEDs ("protected" and "grounded"), an
inductor coil, a couple resistors and transistors, and about 9 or 10
disc capacitors in series. In October 2002 the Belkin cost me $40. I'm
hard pressed to say that it was money well spent, if all that's in there
are some capacitors and resistors. Question: are surge protectors worth
it if all they are is just a bunch of capacitors? I know that my $40
surge protector apparently rolled over and died when hit with a real
surge.

Are you sure the "disc capacitor" wasn't actually a MOV (Metal Oxide
Varistor) ?

They look similar, but the MOV is a semiconductor device that drops in
resistance when the voltage reaches a certain point.

On Sat, 15 Nov 2003 0:15:46 -0600, tommyknocker wrote
(in message ):

As a result of recent events, I have two surge protectors that no longer
function without putting out loud noises on HF. I found that the $5
surge protector that my Yaesu was plugged in to was making a loud
whistling noise which was covered up by the louder warbling noise being
made by the Belkin I had my computer plugged into. So I decided to break
them open to see what was inside. The easiest was Old El Cheapo, held
together with screws. Inside was a length of wire, a switch and ONE disc
capacitor wired into six plugs. IMO that's little better than a plain
old power strip. The Belkin had no screws, so it took a little longer to
crack. The results: a switch, two LEDs ("protected" and "grounded"), an
inductor coil, a couple resistors and transistors, and about 9 or 10
disc capacitors in series. In October 2002 the Belkin cost me $40. I'm
hard pressed to say that it was money well spent, if all that's in there
are some capacitors and resistors. Question: are surge protectors worth
it if all they are is just a bunch of capacitors?


I know that my $40
surge protector apparently rolled over and died when hit with a real
surge.


Durn betcha!

It did exactly as it should have and blew out the (I'm reasonably sure)
capacitors (RadioShack used to carry them, btw)).

That's why they are "cheap" - as I said earlier - they self-destruct rather
than your computers or radio gear self-destructing.

Stinger mentioned Standby Power Supplies. I have a 500 watt APC SPS that was
pretty decently priced and my wife has one of the itsy-bitsy SPS Power Strips
(APC Office 280) and I've seen these "PowerSupply in a Power Strip" /very/
cheap lately - 40U$-55U$.

My wife and I used to run to the front door when the Back-Up 500 signaled
with a short beep; usually we could get to the front porch to hear the
transformer self-destruct.

Sometimes we were the ones with a power outage and the two SPS's allowed us
to "shut down gracefully". Other times we just knew that some residents not
too far away had just lost their power.




Gray Shockley
-------------------------------------------------
They laughed at Columbus, they laughed at Fulton,
they laughed at the Wright brothers. But they
also laughed at Bozo the Clown." - Carl Sagan

Any protector that is damaged by the first surge is grossly
undersized. No effective surge protector can be damaged.
They are not sacrificial devices as urban myth purveyors will
claim.

Why are 'whole house' protectors so effective? One reason:
properly sized. For example, lets say that plug-in protector
can withstand three same size 8/20 usec standard transients.
Then the 'whole house' protector is rated to withstand on the
order of 400 such transients. Properly sized protectors is
but another reason why we install 'whole house' protectors and
don't waste money on plug-in protectors. That 'whole house'
protector costs about $1 per protected appliance. Why would
anyone pay $20 or $50 for a plug-in protector that was both
grossly undersized AND ineffective?

Appliances already have internal protection. Sometimes
surges are too small to even damage the appliance - but
destroy the grossly undersized (and adjacent) surge
protector. What kind of protection is that? Ineffective,
overprices, undersized - and too often recommended by one who
says, "My surge protector sacrificed itself to protect my
computer". This is where ineffective plug-in protectors get
recommended.

Gray Shockley wrote:
Durn betcha!

It did exactly as it should have and blew out the (I'm reasonably
sure) capacitors (RadioShack used to carry them, btw)).

That's why they are "cheap" - as I said earlier - they self-destruct
rather than your computers or radio gear self-destructing.

Stinger mentioned Standby Power Supplies. I have a 500 watt APC
PS that was pretty decently priced and my wife has one of the
itsy-bitsy SPS Power Strips (APC Office 280) and I've seen these
"PowerSupply in a Power Strip" /very/ cheap lately - 40U$-55U$.

My wife and I used to run to the front door when the Back-Up 500
signaled with a short beep; usually we could get to the front
porch to hear the transformer self-destruct.

Sometimes we were the ones with a power outage and the two SPS's
allowed us to "shut down gracefully". Other times we just knew
that some residents not too far away had just lost their power.

In article , w_tom
wrote:

Any protector that is damaged by the first surge is grossly
undersized. No effective surge protector can be damaged. They are
not sacrificial devices as urban myth purveyors will claim.

The characteristics of MOV's are well known. Every time a MOV turns on
due to the device threshold being exceeded they degrade based on how
much power is absorbed.

If you are whom I think you are the facts won't bother you one bit and
further nonsense posts can be expected.

--
Telamon
Ventura, California

A wire also absorbs some power when it shorts a large
current. Does that mean the purpose of a wire is to absorb
electricity? Of course not. MOVs are not installed to absorb
power. But then if one first consults manufacturer
datasheets, then that becomes woefully obvious.

http://www.nteinc.com/Web_pgs/MOV.html
Let's use the 2V130 as example. This device will shunt up to
4500 amps during the standard 8/20 usec surge. A 1000 volt
transient at 4500 amps would be well over 600 joules. But
this device is only rated at 39 joules maximum. How can that
be? Because MOVs, like wire, are not installed to absorb the
energy. They are designed to shunt.

If an MOV was absorbing the transient, then MOV voltage must
increase as more energy is absorbed. That means more voltage
confronts the adjacent appliance. But MOVs don't work that
way. If their purpose was to absorb a transient, then they
must connect in series with the appliance. But MOVs connect
in parallel - a shunt mode device. To be effective as shunt
mode devices (like wire), the MOV must conduct massive
transients and absorb less of that transient. That is what
MOVs do. They shunt. They do not stop, block, absorb, or
filter a transient. They operate like a wire during the
transient. They shunt.

As previously demonstrated from manufacturer datasheets (and
not from wild speculation about what 'joules' measures): If
that MOV in a plug-in protector that can only withstand 3
standard 8/20 microsecond transient, then the larger 'whole
house' protector (that costs about same) will withstand about
300+ such surges. Joules is a measure of MOV life
expectancy. MOVs are not designed to absorb a transient -
which is in direct contradiction to what many web sites,
written by English majors, will claim. The better an MOV,
then the more energy it can shunt - per joule. Read
manufacturer datasheets; not web sites written by English
majors. It is the difference between fact and fiction.

Now for your insults - which apparently are due to
insufficient electrical knowledge. First learn before
insulting others. There is a datasheet. Read it before
posting. Keep it civil - if you can. Posted previously are
accurate electrical engineering facts taken from manufacture
datasheets. Any protector that is damaged by the first surge
is grossly undersized - an ineffective protector usually sold
to those who like to throw money at urban myths.

BTW, MOV degradation is not due to power absorption. It is
due to energy absorption - a major technical difference that
English majors will not understand.

Telamon wrote:
In article , w_tom
wrote:

Any protector that is damaged by the first surge is grossly
undersized. No effective surge protector can be damaged. They
are not sacrificial devices as urban myth purveyors will claim.

The characteristics of MOV's are well known. Every time a MOV turns
on due to the device threshold being exceeded they degrade based
on how much power is absorbed.

If you are whom I think you are the facts won't bother you one bit
and further nonsense posts can be expected.

In article , w_tom
wrote:

A wire also absorbs some power when it shorts a large
current. Does that mean the purpose of a wire is to absorb
electricity? Of course not. MOVs are not installed to absorb
power. But then if one first consults manufacturer
datasheets, then that becomes woefully obvious.

http://www.nteinc.com/Web_pgs/MOV.html
Let's use the 2V130 as example. This device will shunt up to
4500 amps during the standard 8/20 usec surge. A 1000 volt
transient at 4500 amps would be well over 600 joules. But
this device is only rated at 39 joules maximum. How can that
be? Because MOVs, like wire, are not installed to absorb the
energy. They are designed to shunt.

If an MOV was absorbing the transient, then MOV voltage must
increase as more energy is absorbed. That means more voltage
confronts the adjacent appliance. But MOVs don't work that
way. If their purpose was to absorb a transient, then they
must connect in series with the appliance. But MOVs connect
in parallel - a shunt mode device. To be effective as shunt
mode devices (like wire), the MOV must conduct massive
transients and absorb less of that transient. That is what
MOVs do. They shunt. They do not stop, block, absorb, or
filter a transient. They operate like a wire during the
transient. They shunt.

As previously demonstrated from manufacturer datasheets (and
not from wild speculation about what 'joules' measures): If
that MOV in a plug-in protector that can only withstand 3
standard 8/20 microsecond transient, then the larger 'whole
house' protector (that costs about same) will withstand about
300+ such surges. Joules is a measure of MOV life
expectancy. MOVs are not designed to absorb a transient -
which is in direct contradiction to what many web sites,
written by English majors, will claim. The better an MOV,
then the more energy it can shunt - per joule. Read
manufacturer datasheets; not web sites written by English
majors. It is the difference between fact and fiction.

Now for your insults - which apparently are due to
insufficient electrical knowledge. First learn before
insulting others. There is a datasheet. Read it before
posting. Keep it civil - if you can. Posted previously are
accurate electrical engineering facts taken from manufacture
datasheets. Any protector that is damaged by the first surge
is grossly undersized - an ineffective protector usually sold
to those who like to throw money at urban myths.

BTW, MOV degradation is not due to power absorption. It is
due to energy absorption - a major technical difference that
English majors will not understand.

Telamon wrote:
In article , w_tom
wrote:

Any protector that is damaged by the first surge is grossly
undersized. No effective surge protector can be damaged. They
are not sacrificial devices as urban myth purveyors will claim.

The characteristics of MOV's are well known. Every time a MOV turns
on due to the device threshold being exceeded they degrade based
on how much power is absorbed.

If you are whom I think you are the facts won't bother you one bit
and further nonsense posts can be expected.

The notorious Tom troll.

Explaine the meaning of the chart "Peak current per pulse versus pulse
duration" at the top of this page.

http://www.worldproducts.com/MOVPeakPulse.htm

I see you are still up to par with your long winded nonsense and you
still have not learned to post to Usenet properly either.

Up next... a kill file update.

--
Telamon
Ventura, California

not disc caps! they are metal oxide variable resistors. they look just
like caps. keep the shell and replace the mov's. it will be good as new.
buy extras because the mov's can only take so many hits (or just one big
one) before they are ruined. if you arent satisfied with the performance
of the cheaper surge suppressors then look into a transformer based one.
i have two ONAC brand line conditioners. they are more expensive but
they never wear out. (excluding direct lightning hits of course) i got
them surplus at a junk shop that salvaged computer equipment. its been
more than ten years with out power line damage with my set up. i dont
have $40 in both of them but i got lucky. when bought new they are not
cheap.

uh.... thanks for your very productive input barry O grady....... i am
sure that the english lesson was helpful in the understanding of line
spike damping. oh by the way, god_freee_jones? i do not think freee is
a word. use your spell-checker.

Over the years I have replaced dozens of MOVs in my
numerous high-end surge-limiting power strips rather than
shell out another couple hundred dollars for new strips
after major power company events. I get on average a year's
life out of the strips before another power company event
comes along.
The cause of some of these events is known. Another
power company had three-phase lines going over the
street-side power lines. Under certain wind conditions they
would make contact. I observed a large, long 1/2 second
over-voltage event that blew out the breaker panel
suppressor and at least one MOV in each power strip with a
bang and smoke.
Other times lightning would induce the event. I
theorize that a flashover resulted in a nearby power company
voltage regulator's (a big variac) storage of a large amount
of energy due to large following currents. Somehow this
energy then dumps onto the street-side lines, causing
another failure of the surge protectors. The power company
regulator also failed to 8% high and this may have
contributed to the problem.
But the AC system and major household appliances were
not damaged. This indicates that while there was a serious
over-voltage, it was not enough to pierce the insulation on
motor windings and an unprotected wall wart.
Anyway, I bought a few dozen replacement MOVs and 3 or 5
amp pigtail fuses for repairs. Usually just one MOV and
fuse fail per strip. The strip can be recovered with
sufficient skill.
Good surge protector strips have inductors in them to
block the high frequency components of the surge.
Otherwise, plugged-in power transformers without effective
shielding between the primary and secondary (typical) can
pass along these potentially large high-frequency components
to the following circuitry.
In my case, 130V MOVs for the 125VAC service would blow
out at the next event. So I upped the replacements to 150V
with some hope that it will make a difference.
The replacement fuses are standard AGC 250V sized at 3
or 5 Amp. They really take a beating when one of these
events comes along. The inside surface of the glass fuse
body has lots of metal globules embedded in the glass.
Professional lightning protection systems use a
multi-layered approach. It used to be that Polyphaser Corp
sold a book called "The 'Grounds' for Lightning and EMP
Protection" that described this in usable engineering terms.
Now they don't offer it on the website as far as I can tell.
Just salesman's faqs.

Henry










As a result of recent events, I have two surge protectors that no longer
function without putting out loud noises on HF. I found that the $5
surge protector that my Yaesu was plugged in to was making a loud
whistling noise which was covered up by the louder warbling noise being
made by the Belkin I had my computer plugged into. So I decided to break
them open to see what was inside. The easiest was Old El Cheapo, held
together with screws. Inside was a length of wire, a switch and ONE disc
capacitor wired into six plugs. IMO that's little better than a plain
old power strip. The Belkin had no screws, so it took a little longer to
crack. The results: a switch, two LEDs ("protected" and "grounded"), an
inductor coil, a couple resistors and transistors, and about 9 or 10
disc capacitors in series. In October 2002 the Belkin cost me $40. I'm
hard pressed to say that it was money well spent, if all that's in there
are some capacitors and resistors. Question: are surge protectors worth
it if all they are is just a bunch of capacitors? I know that my $40
surge protector apparently rolled over and died when hit with a real
surge.



Email address: "see_signature" - "a0015717"
Newsgroup replies may serve better the public interest.