Maker Pro
Maker Pro

Surge Protector

B

bud--

Jan 1, 1970
0
w_tom said:
Various and routine insults posted by Bud are removed from the
quote.

w_ is hallucinating again. There were no insults in my post.
Bud promotes for plug-in protector manufacturers.

To quote the all-knowing w_ "it is an old political trick. When facts
cannot be challenged technically, then attack the messenger."
And there was nothing in my post about surge protection.
Truth
concerning things not provided by his products such as earth ground
must be negated by insults.

Further hallucinations and completely unrelated to anything in my post.
In developing standards for surge testing, one waveform (numbers no
longer remembered- maybe 100/10000 usec) was proposed and rejected.
That test waveform was rejected because it caused incandescent light
bulb failure. Lightning strike does not cause light bulb failure
meaning that test waveform was not a valid testing standard. Other
test waveforms that were acceptable are now listed as IEEE/ANSI C62.xx
standards.

Geez - something on-topic.

Looking at the relevant technical paper, arcing started in a lamp at
about 30 microseconds of a 50 microsecond surge. (My post recollected a
100 microsecond surge.) Both are far from w_’s 10,000 microseconds.

The paper says for 120V 100W bulbs, the bulb may fail with an 800V
surge; few bulbs survive 1500V.
For 230V European systems, a bulb may fail at 1800V.

In any case, surges can certainly cause burnout of incandescent light
bulbs, which is what I said.
Some protectors would even claim to meet C62.xx standards. They
were playing games with the naivety of many who never bothered to ask
embarrassing questions. How does a protector conform to a test
waveform? It does not. But IEEE/ANSI C62.42 means a protector must
be better?

Totally irrelevant to anything.
Test waveform was rejected as a standard because it did something to
light bulbs that lightning does not - damage the bulb.

The technical paper was written by Francois Martzloff and others.
Martzloff was the US—NIST guru on surges, did much research and had many
published peer-reviewed technical papers on surges.

So who should I believe - w_ or Martzloff? Gee, its a tough call.
 
B

bud--

Jan 1, 1970
0
w_tom said:
Voltage numbers provided by Franc for a 320V 7mm and 20mm MOV are
for 1 ampere; not 1000 A. Voltage numbers for a 1000 A spike would be
1060 volts and just over 1000 volts; not 780V and 740V.

More reasonable numbers for these Vishay VDRH07K320 (45 joule) and
VDRH20X320 (382 joule) MOVs would be 400A and 100A; in next two
paragraphs.

A 45 joule 7mm MOV conducting a 400 A current is 1040 volts. A 382
joule 20 mm MOV conducting same 400 A is only just above 1000 volts.
As joules increase, then the MOV becomes more conductive; absorbed
energy decreases by more than 3%.

For 100A, voltage numbers for that 45 and 382 joule MOVs are 970V and
910V. Energy absorbed by a higher joule MOV decreases by 5%.

As previously stated, energy absorption decreases when MOV joules
increase. More MOV joules means that MOV becomes more conductive.
Better is a more conductive MOV. Why? Better shunt mode protectors
absorb less surge. Shunt mode protector means more conductive (less
power absorbed) is better.

Now to complete an analysis using those datasheet charts. What
happens due to that 3% and 5% reduction in energy absorption? Fact
from the datasheet that Franc did not grasp.

For a typical 30 microsecond 400A transient, the 45 joule MOV has a
life expectancy of slightly more than 10 surges. But a more
conductive 382 joule MOV has a life expectancy of 900 surges. With 8
times more joules, better conductivity means the MOV lasts 50 times
longer. Just another reason why we want MOVs with better
conductivity; to absorb less energy. Life expectancy increases
massively.

I agree that as the energy hit per event becomes a smaller percentage of
the MOV energy rating, the cumulative dissipation capacity is increased
out of proportion. Buying a suppressor with high energy ratings can
greatly increase its life.

But it is not credible that a 3% lower voltage at the MOV (and a 3%
lower energy hit per event) results in an 890% increase in the number of
hits the MOV can withstand. Because a higher energy rated MOV is larger,
the energy dissipated per unit area is lower - a decrease far more than
3%. A low energy dissipation per unit area just does far less damage to
the MOV.
For the 100A surge, life expectancy of a 45 joule MOV is 2,000
surges compared to 80,000 for the 382 joule MOV. Again, 5% less energy
absorbed due to 8 times more joules results in a 40 times increase in
life expectancy.
Ditto.


Demonstrated:
1) As MOV joules increase, then MOV conductivity increases.
2) More MOV joules means less energy absorbed.

In the examples by 3 or 5% - almost trivial as Franc noted.
3) Less energy absorbed also means less degrading of an MOV's
crystalline structure, less degrading, and therefore a significant
increase in MOV life expectancy.

Not because of a 3-5% decrease.
4) MOV joules increased 8 times caused a 40 or 50 times increase in
number of surges; increased MOV life expectancy.

Returning to the original point. MOV are not for absorbing surges.
We install MOVs to shunt (divert, clamp) that surge elsewhere. As
demonstrated earlier, for every joule absorbed by an MOV, maybe 10 or
30 joules are shunted elsewhere.

I don't think it was demonstrated earlier. It depends on the circuit and
the event.

Increased MOV joules makes a better
(more conductive) protector. Less energy absorbed by MOVs also
results in significantly longer MOV life expectancy.

Using Vishay datasheets, MOVs are not installed to absorb surges.

I don't remember that in the Vishay datasheets. Sometimes, like
connecting a MOV across a relay coil, a MOV is installed to absorb
surges. In the case of service panel or plug-in suppressors I agree that
absorbing surges is incidental.
That directly contradicts popular myths. Unfortunately, it does
absorb some energy because an MOV is not perfect.

It has nothing to do with perfect. It has to do with physics. If there
is a voltage across a black box and a current through it for a given
time, energy is dissipated in the box.

I agree with Franc.
 
B

bud--

Jan 1, 1970
0
bud-- said:
But it is not credible that a 3% lower voltage at the MOV (and a 3%
lower energy hit per event) results in an 890% increase in the number of
hits the MOV can withstand. Because a higher energy rated MOV is larger,
the energy dissipated per unit area is lower - a decrease far more than
3%. A low energy dissipation per unit area just does far less damage to
the MOV.

That should be an *8900%* increase and dissipation per unit *volume*.
 
W

w_tom

Jan 1, 1970
0
It has nothing to do with perfect. It has to do with physics. If there
is a voltage across a black box and a current through it for a given
time, energy is dissipated in the box.

This is exactly what w_tom posted repeatedly. When energy
dissipated in a 'magic box' is less, then more energy is dissipated in
earth. Again, this is what w_tom said.

Less energy dissipated in the MOV means better protection. Franc
says MOVs work better by absorbing more energy. Then w_tom
repeatedly requested numbers from datasheets. When Franc finally
conceded, then his own numbers showed how energy consumption
decreases. Franc only did half the work. That reduced energy
consumption also coincided with a massive increase in life expectancy
- 40 or 50 times longer. Why? We want MOVs to absorb less energy.

w_tom also provided another example. For every joule that an MOV
absorbed (a bad thing), then something like 30 times more energy was
dissipated elsewhere (a good thing). Better shunt mode protectors
absorb less energy and are more conductive - shunt more energy and
absorb less. Increased MOV joules is equivalent to larger gauge
wire. Both absorb energy (a bad thing) while shunting energy to be
absorbed elsewhere (a good thing).

Franc Zabkar claims that MOVs protect better by absorbing more
energy. That would be true for series mode protectors. But MOVs are
shunt mode protectors. Franc is simply wrong as demonstrated again by
two above examples - with numbers.

We can install a protector that is even better (more conductive)
but costs much more money. This protector uses avalanche diodes. A
275 volt protector could easily limit voltage to 500 instead of 900+.
Better protection because that semiconductor protector is even more
conductive. Better protection because only 500 volts instead of 1000
volts confronts protection inside appliances.

That is where Franc and this poster disagree. Franc says MOVs
protect by absorbing the surge. Even datasheets demonstrate that
better protectors absorb less energy. Joules in an MOV do not mean it
absorbs more surge as Franc has repeatedly assumed. More joules in an
MOV is equivalent to a heavier gauge wire - as was posted so many
times previously by whom? For a more conductive wire or a longer
lasting MOV - we increase wire gauge or MOV joules.

MOV is a shunt mode device. It performs even better when more surge
energy dissipates elsewhere. Better protectors dissipated more surge
into earth - not through household appliances. Better shunt mode
protectors absorb less surge energy; therefore cause less voltage to
confront electronics. An MOV that absorbs more energy is an inferior
protector - as demonstrated how many times with numbers? Franc
disagrees? Bud agrees that more energy absorbed by an MOV means
better protection? Where are the numbers for this claim? Those
numbers do not exist.

Let's not forget the only reason for these numbers. Franc claims
that MOVs work better by absorbing more surge energy. That is the
question. Shunt mode protectors work better by absorbing less
energy. And this is why earth ground is so essential to effective
surge protection. The effective MOV protector has a short (more
conductive) connection to earth ground. Why? Better protectors
dissipate more energy in earth. Just another in the so many reasons
why a protector is only as effective as its earth ground.

Bud cannot agree with that. Protectors promoted by Bud have no
dedicated earthing wire. Where is that energy dissipated? Bud would
have us believe as Franc has claimed: protector that absorbs more
surge energy is better. Demonstrated by numbers provided even by
Franc: better MOV protectors (more joules) absorb less energy, last
longer, and shunt (clamp, divert, bond, connect, conduct) more surge
energy into earth. But again, a protector is only as good as its
earth ground - where the surge must be dissipated.

In example after numerical example, a better protector (MOV with
more joules) means less energy absorbed by the protector AND more
energy shunted to and absorbed by earth. Just another reason why
better protectors have that short connection to earth ground. As
usual, examples with numbers demonstrate validity - what an effective
protector does. It shunts - absorbs less energy - dissipates more
energy in earth (if that superior earthing connection exists).
 
B

bud--

Jan 1, 1970
0
bud-- said:
That should be an *8900%* increase and dissipation per unit *volume*.

Opps - was closer before. Replace the paragraph with:

The 20mm MOV withstands 10.6 times the number of surges that would be
expected, correcting for its larger energy rating. It is not credible
that a 3% lower voltage at the MOV (and a 3%lower energy hit per event)
would cause a 960% rise in the number of surges the MOV can withstand.

But the 20mm MOV is larger diameter with about 8 times the volume. Since
a MOV dissipates the energy through the whole volume, the energy
dissipated per square centimeter in the 7mm MOV is 8 times the energy
dissipated per square centimeter in the 20mm MOV. The lower energy
dissipation per square centimeter in the 20mm MOV causes far less
heating and far less damage to the MOV and the MOV is able to withstand
more surges. A 3% lower energy per hit helps but is a minor contributor.



IMHO w_'s latest rant is near incomprehensible.

I still agree with Franc.
 
A

a t e c 7 7

Jan 1, 1970
0
Michael said:
I guess he didn't pay for his hosting on time. You do have to admit
that its an improvement.
Typical imported junk salesperson
 
T

Trevor Wilson

Jan 1, 1970
0
Michael A. Terrell said:
I guess he didn't pay for his hosting on time. You do have to admit
that its an improvement.

**Nope. My arsehole of a webhost shut up shop, without warning. I paid a
year in advance and got three months. He had all my files stored on his
server (mine were lost in a hard disk crash. My backups were unreadable -
NEVER trust optical media for long term storage). He doesn't answer his
'phone (not even his mobile). I have been unable to retrieve my files, so I
can ftp them to my new host. I now need to find the time/money to construct
a new site. I will be backing up on two hard disks on a RAID 5 system.
 
P

Poxy

Jan 1, 1970
0
Trevor said:
**Nope. My arsehole of a webhost shut up shop, without warning. I
paid a year in advance and got three months. He had all my files
stored on his server (mine were lost in a hard disk crash. My backups
were unreadable - NEVER trust optical media for long term storage).
He doesn't answer his 'phone (not even his mobile). I have been
unable to retrieve my files, so I can ftp them to my new host. I now
need to find the time/money to construct a new site. I will be
backing up on two hard disks on a RAID 5 system.

RAID5 needs a minimum of 3 disks.

And you might want to remove the URL from your sig until your site is
working again.
 
P

Poxy

Jan 1, 1970
0
Trevor said:
**Nope. My arsehole of a webhost shut up shop, without warning. I
paid a year in advance and got three months. He had all my files
stored on his server (mine were lost in a hard disk crash. My backups
were unreadable - NEVER trust optical media for long term storage).
He doesn't answer his 'phone (not even his mobile). I have been
unable to retrieve my files, so I can ftp them to my new host. I now
need to find the time/money to construct a new site. I will be
backing up on two hard disks on a RAID 5 system.

Oh, and a copy of your site is here:
http://web.archive.org/web/20060819214623/http://www.rageaudio.com.au/

But I'd suggest you re-do your site using a CMS like WordPress using a nice
template (there are hundreds of free ones available). Makes for a
nice-looking site and is very easy to update. Most hosting services that
offer Cpanel have it available for installation under the Fantastico option.
 
P

Pete

Jan 1, 1970
0
Trevor said:
**Nope. My arsehole of a webhost shut up shop, without warning. I
paid a year in advance and got three months. He had all my files
stored on his server (mine were lost in a hard disk crash. My backups
were unreadable - NEVER trust optical media for long term storage).

I've jumped in here without knowing exactly what you're talking about
(my damn ISP's news server crashed and they wiped the spool), but if
it's about losing all the files from http://www.rageaudio.com.au then
try this:

http://web.archive.org/web/*/http://www.rageaudio.com.au

The Internet Archive seems to have taken lots of snapshots of that web
site. Hopefully, you'll be able to get something back.

Regards, Peter
 
T

Trevor Wilson

Jan 1, 1970
0
S

swanny

Jan 1, 1970
0
Poxy said:
Oh, and a copy of your site is here:
http://web.archive.org/web/20060819214623/http://www.rageaudio.com.au/

But I'd suggest you re-do your site using a CMS like WordPress using a nice
template (there are hundreds of free ones available). Makes for a
nice-looking site and is very easy to update. Most hosting services that
offer Cpanel have it available for installation under the Fantastico option.

Yes, several CMS available. Joomla, Typo3 etc. Pick one that suits the type of
site you are hoping to create and maintain.
Usually all installable from Cpanel/Fantastico. I had trouble finding a decent,
reasonably-priced local hosting company recently and have now shifted everything
offshore to siteground.com.
 
F

Franc Zabkar

Jan 1, 1970
0
Exactly. Now you are starting to grasp why lightning surges
typically don't explode light bulbs.

Elsewhere in this thread it was shown that a 1800V transient is enough
take out a 240V 100W bulb.

By my calculation, the energy involved would be only ...

E = 1800V x 1800V / 60 ohms x 20us = 1.1J
Why a 70 joule MOV dissipates so few watts.

You still don't understand. The transient power dissipation can be 1MW
(1000V x 1000A). A MOV doesn't need to dissipate a lot of *average*
power.
And why a surge so large to stress an MOV to maximum
results in 10 or more times energy absorbed elsewhere. Dissipating
most of the energy eslewhere is why MOVs are so effective shunt mode
protectors. More energy is absorbed elsewhere (in earth) and less
energy is absorbed in inside MOVs.

Joules consumed by a light bulb determines things such as light
efficiency. Light bulbs are designed to absorb joules. But absorbing
more joules is bad for MOVs. How to reduce the joules consumed by a
shunt mode protector? Increase MOV joules rating (same reason we
increase wire size). An MOV with more joules means that MOV absorbs
less energy - which is exactly what we want for surge protection.

This was shown to be insignificant on numerous occasions. A 5%
reduction in energy absorption is not a design criterion for surge
protectors.
Until you grasp that fact from datasheet charts, then you will not
understand what MOVs do. MOV does not provide better protection by
absorbing more energy. MOV provides better protection by absorbing
less energy AND when shunting more energy to earth. What makes a
better protector? More MOV joules means it absorbs less energy.
More MOV joules means a better conductive connection (shunt) to earth.
What makes a better protection 'system'? Better earthing.

MOVs are shunt mode protectors. They don't care about earthing. All
they need to do is to *shunt* the surge away from the parallel
attached appliance. That's why two-wire appliances often have a MOV
between active and neutral.
You formulas are correct. But assumed is that (for example) voltage
is a mathematically independent variable. What happens when an MOV
has higher joules? Then its Vp decreases resulting in more energy
shunted to earth and less energy absorbed by the MOV.

5% is insignificant.
In simple terms, MOVs perform a job more like a switch. A more
conductive switch, means a better protector. That means more MOV
joules so that less energy is absorbed by the MOV.

A MOV is not a switch, it is a *clamp*. A *perfect* MOV cannot *ever*
have a zero resistance. If it did, then it would short out the mains
supply.
Series mode protectors operate better by absorbing more energy.
Shunt mode protectors operate better by absorbing less energy. MOV is
a shunt mode protector. Again, study charts in those manufacturer
datasheets. The numbers that confirm the above concepts are in those
manufacturer datasheet charts.

As an MOV joule rating increases, then MOV absorbs less energy.

5% is insignificant.
Less energy absorbed means longer life expectancy.

A MOV that absorbs 9.95J rather than 10J will not last significantly
longer.
Effective
protectors also shunt surges and remain functional - another fact from
those charts. A protectors joules rating must be high enough as to
absorb less energy, shunt more energy to earth, and therefore remain
functional after direct lightning strikes.

5% is insignificant.
Install protectors to make direct lightning strikes irrelevant. A
properly sized (sufficient joules) and earthed protector means
protection inside appliances is not overwhelmed and homeowner should
never even know the surge existed. Too few MOV joules means the
protector absorbs more energy, vaporizes, and may even result in these
scary pictures:
http://www.hanford.gov/rl/?page=556&parent=554
http://www.westwhitelandfire.com/Articles/Surge Protectors.pdf
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html

I agree that one should opt for higher rated protectors/MOVs. I don't
agree that higher rated MOVs absorb significantly less energy. That is
demonstrably false, even by your own analyses.

- Franc Zabkar
 
F

Franc Zabkar

Jan 1, 1970
0
Voltage numbers provided by Franc for a 320V 7mm and 20mm MOV are
for 1 ampere; not 1000 A. Voltage numbers for a 1000 A spike would be
1060 volts and just over 1000 volts; not 780V and 740V.

Sorry, you're right. Nevertheless, my conclusions are unaffected. In
fact you've just demonstrated how little the voltage changes in
response to large changes in current, ie 1.35:1 V/V as opposed to
1000:1 A/A.
More reasonable numbers for these Vishay VDRH07K320 (45 joule) and
VDRH20X320 (382 joule) MOVs would be 400A and 100A; in next two
paragraphs.

A 45 joule 7mm MOV conducting a 400 A current is 1040 volts. A 382
joule 20 mm MOV conducting same 400 A is only just above 1000 volts.
As joules increase, then the MOV becomes more conductive; absorbed
energy decreases by more than 3%.

For 100A, voltage numbers for that 45 and 382 joule MOVs are 970V and
910V. Energy absorbed by a higher joule MOV decreases by 5%.

As previously stated, energy absorption decreases when MOV joules
increase. More MOV joules means that MOV becomes more conductive.
Better is a more conductive MOV. Why? Better shunt mode protectors
absorb less surge. Shunt mode protector means more conductive (less
power absorbed) is better.

You cannot seriously claim that a figure of 3% or 5% is significant.
It amounts to *nothing*. It is certainly not a valid reason to choose
a higher energy MOV over a lower energy one. It makes about as much
sense as choosing a 5W zener over a 400mW zener when the circuit
dissipation calls for 100mW. The benefits of a larger MOV are an
ability to withstand a larger surge, and an ability to withstand more
surges in the same time. The latter is reflected in the average power
rating.

In fact the difference of 5% is a consequence of the fact that MOVs
are imperfect. If a MOV had a perfectly sharp IV characteristic, then
there would be no difference in the absorbed energy in the above
example.
Now to complete an analysis using those datasheet charts. What
happens due to that 3% and 5% reduction in energy absorption? Fact
from the datasheet that Franc did not grasp.

For a typical 30 microsecond 400A transient, the 45 joule MOV has a
life expectancy of slightly more than 10 surges.

E = Vp x 400A x 30us = 12J (if Vp = 1000V)
But a more
conductive 382 joule MOV has a life expectancy of 900 surges. With 8
times more joules, better conductivity means the MOV lasts 50 times
longer.

The resistance of a 20mm MOV hit by a 1000V 1000A surge is 1.00 ohms.

The resistance of a 7mm MOV hit by a 1050V 1000A surge is 1.05 ohms.

A 10W 1 ohm resistor and a 250mW 1 ohm resistor both have the same
resistance.
Just another reason why we want MOVs with better
conductivity; to absorb less energy. Life expectancy increases
massively.

A figure of 3% is *insignificant*. A MOV doesn't last longer because
it absorbs 3% less energy. A 45J MOV will be significantly degraded by
a 12J surge simply because it is rated to handle 45J. OTOH a 382J MOV
will not be greatly affected by the same surge because it is rated for
382J, not because its IV characteristic reduces the impact to only
11.4J (12J - 5%).

Think of the larger MOV as 8 smaller MOVs in parallel. In fact, if the
energy rating of a MOV is proportional to its area (assuming equal
thickness), then we have ...

Rating of 20mm MOV = (20mm/7mm)^2 x 45J = 8.2 x 45 = 367J
For the 100A surge, life expectancy of a 45 joule MOV is 2,000
surges compared to 80,000 for the 382 joule MOV. Again, 5% less energy
absorbed due to 8 times more joules results in a 40 times increase in
life expectancy.

The fact that 5% less energy is absorbed is of no practical
significance. It's the energy rating and average power dissipation
that are important, the latter in the case of repetitive transients.
Demonstrated:
1) As MOV joules increase, then MOV conductivity increases.
Insignificant.

2) More MOV joules means less energy absorbed.

5% is insignificant.
3) Less energy absorbed also means less degrading of an MOV's
crystalline structure, less degrading, and therefore a significant
increase in MOV life expectancy.

5% less energy will have an insignificant impact on the MOV's life
span.
4) MOV joules increased 8 times caused a 40 or 50 times increase in
number of surges; increased MOV life expectancy.

More joules, better conductivity, and less energy absorbed means
less MOV degradation during each surge. That is what we want from
MOVs. More surge energy shunted elsewhere. Less energy absorbed by
an MOV.

5% is *nothing*. Less energy absorbed in relation to a MOV's rating is
what determines its life expectancy. It's not the absolute energy
figure itself which is the determinant.

For example, if a single MOV absorbs 10J, then 8 such MOVs in parallel
should experience exactly the same degradation (less 5%) when
absorbing a combined amount of 80J. Alternatively, for the same 10J
surge, each of those 8 MOVs will see only 1.25J. That's why a larger
MOV lasts longer.
Returning to the original point. MOV are not for absorbing surges.
We install MOVs to shunt (divert, clamp) that surge elsewhere.

You have no idea how a clamp works. Energy is absorbed as a direct
consequence of clamping action. The MOV mitigates the affect of the
surge by reducing the surge voltage. In so doing it diverts the
majority of the surge current through itself, and absorbs an amount of
energy given by ...

Energy = Volts x Amps x time
As
demonstrated earlier, for every joule absorbed by an MOV, maybe 10 or
30 joules are shunted elsewhere.

I have no idea what you are talking about. Are you saying that these
extra joules pass mysteriously through the MOV on their way to earth?
Increased MOV joules makes a better
(more conductive) protector. Less energy absorbed by MOVs also
results in significantly longer MOV life expectancy.

True, but 5% less energy will have no significant impact.
Using Vishay datasheets, MOVs are not installed to absorb surges.
That directly contradicts popular myths.
Unfortunately, it does
absorb some energy because an MOV is not perfect.

A *perfect* MOV will *always* absorb energy. That's how it is intended
to work.

For example, a perfect MOV installed in a 240VAC appliance should have
a breakover voltage rating of 275V, say. Above this voltage the MOV
should clamp any surge to 275V, but below this voltage the MOV should
remain open circuit. Let's say the DC rating of this perfect MOV is
380VDC. Then *any* DC surge clamped/diverted by this perfect MOV will
cause the MOV to absorb E = 380 x Isurge x dt joules.

A perfect MOV will never absorb 0J. For this to be possible, the MOV
would need to clamp the surge to Vp = 0V, which would mean that it
would be shorting the mains supply.
Increasing MOV
joules means an MOV becomes more conductive and degrades less during
each surge. Install more joules in a shunt mode protector for better
conductivity and longer life expectancy.

- Franc Zabkar
 
W

w_tom

Jan 1, 1970
0
I agree that as the energy hit per event becomes a smaller percentage of
the MOV energy rating, the cumulative dissipation capacity is increased
out of proportion. Buying a suppressor with high energy ratings can
greatly increase its life.

Return to what Franc Zabkar did not grasp. Bud must say anything to
have everyone confused as to what an MOV does. Profits are at risk.

A better protector absorbs less energy. That is the point. As MOV
joules increase, then energy dissipated by MOVs decreases (and life
expectancy increases). Franc Zabkar repeatedly claims that an MOV
provided protection by absorbing the surge. That is not an MOV's
purpose as even demonstrated by numbers for better MOVs. As MOV
joules increase, then energy absorption decreases. We want shunt mode
protectors to absorb less energy. A better MOV absorbs less energy.
AND better protectors using other technologies to absorb even less
energy. Why? In every case, the better shunt mode protector absorbs
less energy - in direct contradiction to what Franc Zabkar has posted.

MOVs are shunt mode devices. MOVs are effective when surge energy
is shunted (diverted, connected, clamped, conducted, bonded)
elsewhere. That elsewhere is earth ground. What makes a conductive
MOV so effective? A short path to earth ground also called a 'whole
house' protector.

MOVs are for shunting energy elsewhere; not for absorbing surge
energy. Franc Zabkar does not grasp that concept. All this other
stuff remains completely irrelevant to what Franc Zabkar denies. In
every example of a superior shunt mode protector, the protector
absorbs less energy. Shunting is why MOV based protectors require a
conductive (short) path to earth ground - where surge energy is
dissipated. A shunt mode protector without that conductive path to
earth may shunt that surge destructively elsewhere - such as through
household appliances.

Franc - your posts erroneously define MOVs doing the task of a
series mode protector. Series mode protectors protect by absorbing
energy. Shunt mode protectors operate by shunting (diverting) energy
elsewhere. MOVs are shunt mode protectors. Less energy absorbed by a
shunt mode protector means better protection. Shunt mode protectors
must connect to something that non-destructively absorbs that energy -
ie earth ground.

Bud fears others might learn this technology. Plug-in protectors
(shunt mode protectors) don't have that short earthing connection. No
earth ground means nothing to absorb the energy. Bud must post
incessantly to confuse the concept. Better MOVs not only absorb less
energy. Better MOV protectors also need that short connection to
earth ground. If you learn that, then you will learn why a plug-in
protector with no dedicated earthing wire is a poor protectors. With
no earth to absorb the surge, then where does it shunt to? Bud will
say anything to obfuscate that question.
 
B

bud--

Jan 1, 1970
0
w_tom said:
Return to what Franc Zabkar did not grasp. Bud must say anything to
have everyone confused as to what an MOV does. Profits are at risk.

Franc did not grasp that I must say anything .....???

Ho hum - repeating:
“To quote the all-knowing w_ ‘it is an old political trick. When facts
cannot be challenged technically, then attack the messenger.’ "

A better protector absorbs less energy. That is the point. As MOV
joules increase, then energy dissipated by MOVs decreases (and life
expectancy increases).

As Franc and I have both explained, decrease in energy absorption is
trivial, and makes a trivial contribution to the increase in the
cumulative energy absorption of a MOV. It is idiotic for w_ to argue
this point because it is irrelevant to his major agenda.

Franc Zabkar repeatedly claims that an MOV
provided protection by absorbing the surge.

Bullcrap. Franc repeatedly points out that MOVs *intrinsically* absorb
energy, not that they protect by absorbing energy.

w_ thinks a “perfect’ MOV would not absorb energy - reflecting the
physics in the alternate universe where he lives.

In some applications, like a MOV across relay coil, the total protection
is by absorbing. In other applications absorbing is incidental to
protection.
MOVs are for shunting energy elsewhere; not for absorbing surge
energy.

MOVs are for clamping. That may or may not result in shunting energy. Or
MOVs may just absorb.

With a MOV across a relay coil where is the energy shunted?
Franc Zabkar does not grasp that concept.

w_ can not grasp what Franc is saying.
Shunting is why MOV based protectors require a
conductive (short) path to earth ground - where surge energy is
dissipated. A shunt mode protector without that conductive path to
earth may shunt that surge destructively elsewhere - such as through
household appliances.

If you want reliable information on surges and surge protection read:
http://omegaps.com/Lightning Guide_FINALpublishedversion_May051.pdf
- the title is "How to protect your house and its contents from
lightning: IEEE guide for surge protection of equipment connected to AC
power and communication circuits" published by the IEEE in 2005 (the
IEEE is the dominant organization of electrical and electronic engineers
in the US).
And also:
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf
- this is the "NIST recommended practice guide: Surges Happen!: how to
protect the appliances in your home" published by the US National
Institute of Standards and Technology in 2001

The IEEE guide is aimed at those with some technical background. The
NIST guide is aimed at the unwashed masses. There are minor adjustments
for Australia because people stand upside down. But Australia uses the
same physics and is not in w_'s alternate universe.

w_ does not grasp what either guide is says. Both say plug-in
suppressors are effective.
Bud fears others might learn this technology.

Bud hopes people will read reputable sources, like the IEEE and/or NIST
guides.

No
earth ground means nothing to absorb the energy.

w_ has a religious belief (immune from challenge) that surge protection
must use earthing. Thus in his view plug-in suppressors (which are not
well earthed) can not possibly work. The IEEE guide explains plug-in
suppressors work by CLAMPING the voltage on all wires (signal and power)
to the common ground at the suppressor. Plug-in suppressors do not work
primarily by earthing (or absorbing). The guide explains earthing
occurs elsewhere. (Read the guide starting pdf page 40).

Note that all interconnected equipment needs to be connected to the same
plug-in suppressor, or interconnecting wires need to go through the
suppressor. External connections, like phone, also need to go through
the suppressor. Connecting all wiring through the suppressor prevents
damaging voltages between power and signal wires. These multiport
suppressors are described in both guides.
Bud must post
incessantly to confuse the concept.

w_ must post incessantly because his religious belief has been
challenged. Just like arguing with a Jehovah’s Witness.

w_ can’t figure what both Franc and I have been saying.
And w_ can’t figure out how plug-in suppressors work even though it is
explained in the IEEE guide.


For excellent information on surges and surge protection read the IEEE
and NIST guides. Both say plug-in suppressors are effective.

There are 98,615,938 other web sites, including 13,843,032 by
lunatics, and w_ can't find another lunatic that says plug-in
suppressors are NOT effective. All you have is w_'s opinions based on
his religious belief in earthing.
 
W

w_tom

Jan 1, 1970
0
On Fri, 20 Jul 2007 06:39:35 -0700,w_tom<[email protected]> put finger
You cannot seriously claim that a figure of 3% or 5% is significant.
It amounts to *nothing*. It is certainly not a valid reason to choose
a higher energy MOV over a lower energy one. It makes about as much
sense as choosing a 5W zener over a 400mW zener when the circuit
dissipation calls for 100mW. The benefits of a larger MOV are an
ability to withstand a larger surge, and an ability to withstand more
surges in the same time. The latter is reflected in the average power
rating.

Again the point is being avoided - a point directly traceable to
Tim's original question. Franc claims shunt mode protectors work by
absorbing surges. In each case, a better protector absorbs less
energy. MOVs with more joules absorb less energy. Replacing MOVs
with avalanche diodes absorb even less energy. Using a gas discharge
tube (as was the standard solution almost 100 years ago) absorbs even
less energy, Absorbing less energy is what a shunt mode protector
does - equivalent to what a wire does. Energy is shunted (diverted,
clamped, connected) elsewhere. That 'elsewhere' is earth ground.

Bud so dislikes this reality because his protectors don't have a low
impedance earthing connection. Why is earthing THE most critical
component in a shunt mode 'system'? An MOV, et al becomes as
conductive as possible. A surge is shunted (clamped, diverted) to
earth ground. Earth dissipates the surge - not a protector. An MOV
that shunts 20 or 30 times more energy to earth (than is absorbed) is
a best protector for the dollar.

MOV does not protect by absorbing surge energy. MOV protects by
shunting that energy elsewhere - into earth.

The bottom line about surge protection:
Only component required in a surge protection system is earth ground.
Either a surge is connected directly to earth OR we install an MOV
type protector to make a temporary earthing connection. Earthing
electrode is the 'protection'. 'Protector' is either a hard wire
(cable TV or satellite dish) or a 'whole house' type protector (for
telephone or AC electric).

MOV and wire only absorb energy because each is not perfect. Both
absorb trivial energy to shunt massive energy elsewhere. Both become
even better protectors when they absorb less energy. Franc - that is
the point. Better protectors in every case absorb less energy. More
joules in an MOV means it absorbs less energy - especially when the
MOV is so grossly undersized as to operate at the end of that hock
stick upswing. Why do you keep trying to claim a better protector
will absorb more surge energy? Why do you keep arguing irrelevance?

Tim asked whether a surge protector was recommended. Yes, but one
that earths surges. One that is sufficiently size so as to be a
better conductor - not create these scary pictures:
http://www.hanford.gov/rl/?page=556&parent=554
http://www.westwhitelandfire.com/Articles/Surge Protectors.pdf
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html

Since an MOV operates by shunting (absorbing less energy), then the
protector will only be as effective as its earth ground. Earth is
where energy is absorbed. No earth ground means an MOV has nothing to
shunt to - provides no effective protection. Tim should install a
protector that actually earths surges - by becoming as conductive as
is practicable.
 
F

Franc Zabkar

Jan 1, 1970
0
Again the point is being avoided - a point directly traceable to
Tim's original question. Franc claims shunt mode protectors work by
absorbing surges. In each case, a better protector absorbs less
energy. MOVs with more joules absorb less energy.

A reduction of 3% (your numbers) is insignificant.
Replacing MOVs
with avalanche diodes absorb even less energy. Using a gas discharge
tube (as was the standard solution almost 100 years ago) absorbs even
less energy,

E = Vp x Ip x dt for *all* shunt mode protectors.
Absorbing less energy is what a shunt mode protector
does - equivalent to what a wire does.

What will happen if you place a wire across a mains supply?
Energy is shunted (diverted,
clamped, connected) elsewhere. That 'elsewhere' is earth ground.

This is the IV characteristic of a perfect shunt mode protector:

I
| +I ^
| |
| |
-V ______0_____| +V ---> V
|
|
|
| -I

Nowhere is the resistance (R=V/I) of the protector equal to zero.


This is the IV characteristic of a perfect wire, ie one with zero
resistance:

I
| +I ^
| |
| |
|V=0 ---> V
|
|
|
| -I
Bud so dislikes this reality because his protectors don't have a low
impedance earthing connection. Why is earthing THE most critical
component in a shunt mode 'system'?

Earthing is irrelevant to a shunt mode system, unless the surge/spike
is being shunted to earth.
An MOV, et al becomes as
conductive as possible. A surge is shunted (clamped, diverted) to
earth ground. Earth dissipates the surge - not a protector. An MOV
that shunts 20 or 30 times more energy to earth (than is absorbed) is
a best protector for the dollar.

Energy does *not* pass mysteriously through a MOV on its way to earth.
MOV does not protect by absorbing surge energy. MOV protects by
shunting that energy elsewhere - into earth.

Explain how a shunt mode protector (eg transorb) connected across the
generator terminals in an airplane utilises an earth connection?
The bottom line about surge protection:
Only component required in a surge protection system is earth ground.

A two-wire appliance has no earth ground other than the earth-neutral
bond in a MEN system. A surge suppressor between A-N is required
because only one end of a common mode surge entering the premises is
shunted to ground at the meter box.
Either a surge is connected directly to earth OR we install an MOV
type protector to make a temporary earthing connection. Earthing
electrode is the 'protection'. 'Protector' is either a hard wire
(cable TV or satellite dish) or a 'whole house' type protector (for
telephone or AC electric).

MOV and wire only absorb energy because each is not perfect.

A *perfect* shunt mode protector *always* absorbs energy. That's in
the nature of its design. Please place an X on the IV characteristic
curve that I have drawn above, showing any point where the absorbed
energy is zero.
Both
absorb trivial energy to shunt massive energy elsewhere. Both become
even better protectors when they absorb less energy. Franc - that is
the point. Better protectors in every case absorb less energy.

Yes, a better shunt mode protector will have a vertical IV
characteristic, not one shaped like an ice hockey stick. And yes, it
will absorb less energy. But a 20mm MOV will only absorb 3% less
energy (your numbers) than a 7mm MOV.
More
joules in an MOV means it absorbs less energy - especially when the
MOV is so grossly undersized as to operate at the end of that hock
stick upswing. Why do you keep trying to claim a better protector
will absorb more surge energy? Why do you keep arguing irrelevance?

I have *never* claimed that. I have always said that a bigger MOV will
only absorb about 3-5% less energy than a smaller one. The bigger MOV
is better because it will sustain larger surges without damage, and
because it can sustain more surges, not because it can reduce the
impact of the same surge current by a mere 5%.
Tim asked whether a surge protector was recommended. Yes, but one
that earths surges. One that is sufficiently size so as to be a
better conductor - not create these scary pictures:
http://www.hanford.gov/rl/?page=556&parent=554
http://www.westwhitelandfire.com/Articles/Surge Protectors.pdf
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html

Since an MOV operates by shunting (absorbing less energy), then the
protector will only be as effective as its earth ground. Earth is
where energy is absorbed. No earth ground means an MOV has nothing to
shunt to - provides no effective protection. Tim should install a
protector that actually earths surges - by becoming as conductive as
is practicable.

A MOV is only interested in the potential between its two terminals.
It doesn't care where the surge current goes - it just attempts to
maintain its terminal voltage as low as possible.

- Franc Zabkar
 
B

bud--

Jan 1, 1970
0
w_tom wrote:


I will try not to repeat what Franc has just posted - I agree with him
completely.

Bud so dislikes this reality because his protectors don't have a low
impedance earthing connection. Why is earthing THE most critical
component in a shunt mode 'system'?

The elephant in the room is w_’s religious belief in earthing.
Apparently w_ can not consider that the intrinsic action of a MOV is
*clamping*, because it threatens his religious belief in earthing, which
requires shunting.

But the IEEE guide explains plug-in suppressors work by CLAMPING the
voltage on all wires (signal and power) to the common ground at the
suppressor. Plug-in suppressors do not work primarily by earthing (or
shunting or absorbing). The guide explains earthing occurs elsewhere.
(Read the guide starting pdf page 40).
http://omegaps.com/Lightning Guide_FINALpublishedversion_May051.pdf
MOV does not protect by absorbing surge energy. MOV protects by
shunting that energy elsewhere - into earth.

Religious belief in earthing #2.

Still not explained by w_ - for a MOV connected across a relay coil,
where is energy shunted to. (And then there is Franc’s airplane.)

And of course, plug-in suppressors do not work primarily by shunting - a
major violation for w_ (but not for the IEEE or anyone else). They do
not work primarily by absorbing either.
The bottom line about surge protection:
Only component required in a surge protection system is earth ground.
Either a surge is connected directly to earth OR we install an MOV
type protector to make a temporary earthing connection. Earthing
electrode is the 'protection'.

The religious belief in earthing - #3.
Tim asked whether a surge protector was recommended. Yes, but one
that earths surges. One that is sufficiently size so as to be a
better conductor - not create these scary pictures:
http://www.hanford.gov/rl/?page=556&parent=554

w_ can't understand his own hanford link. It is about "some older
model" power strips and says overheating was fixed in the US with a
revision to UL1449 that requires thermal disconnects. That was 1998.
Perhaps w_ thinks you are not as smart in Australia?
Since an MOV operates by shunting (absorbing less energy), then the
protector will only be as effective as its earth ground. Earth is
where energy is absorbed. No earth ground means an MOV has nothing to
shunt to - provides no effective protection.

Religious belief in earthing #4?

Because w_ is evangelical in his belief in earthing, he uses google
groups to search for “surge” to spread his beliefs. Among his primary
beliefs is that plug-in suppressors can’t possibly work.
Perhaps w_’s nonsense about MOVs is an attempt at a ‘scientific’
attack on plug-in suppressors. w_ knows that in a direct attack he will
get hammered.
Tim should install a
protector that actually earths surges - by becoming as conductive as
is practicable.

Tim should read reliable sources for information, like the IEEE and NIST
guides.

Both guides say plug-in suppressors are effective.

w_ has never produced a link to a source that says plug-in suppressors
are NOT effective. Or that agrees with his nonsense about MOVs.

Never explained by w_:
- Why do the only 2 examples of protection in the IEEE guide use plug-
in suppressors?
- Why does the NIST guide says plug-in suppressors are "the easiest
solution"?
- Where is energy shunted to for a MOV connected across a relay coil?
 
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