Surge Protector

Various and routine insults posted by Bud are removed from the quote. Bud promotes for plug-in protector manufacturers. Truth concerning things not provided by his products such as earth ground must be negated by insults.

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.

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?

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

Reply to
w_tom
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w_ is hallucinating again. There were no insults in my post.

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.

Further hallucinations and completely unrelated to anything in my post.

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.

Totally irrelevant to anything.

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.

-- bud--

Reply to
bud--

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.

Ditto.

In the examples by 3 or 5% - almost trivial as Franc noted.

Not because of a 3-5% decrease.

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

Increased MOV joules makes a better

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.

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.

-- bud--

Reply to
bud--

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

-- bud--

Reply to
bud--

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).

Reply to
w_tom

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.

-- bud--

Reply to
bud--

I guess he didn't pay for his hosting on time. You do have to admit that its an improvement.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
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Reply to
Michael A. Terrell

We had 33100 strikes in one storm a few days ago, in the central part of Florida. The usual is around 4000 per big storm.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
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Reply to
Michael A. Terrell

Typical imported junk salesperson

Reply to
a t e c 7 7

On Tue, 17 Jul 2007 07:55:23 -0700, w_tom put finger to keyboard and composed:

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

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.

This was shown to be insignificant on numerous occasions. A 5% reduction in energy absorption is not a design criterion for surge protectors.

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.

5% is insignificant.

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.

5% is insignificant.

A MOV that absorbs 9.95J rather than 10J will not last significantly longer.

5% is insignificant.

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

--
Please remove one 'i' from my address when replying by email.
Reply to
Franc Zabkar

On Fri, 20 Jul 2007 06:39:35 -0700, w_tom put finger to keyboard and composed:

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.

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.

E = Vp x 400A x 30us = 12J (if Vp = 1000V)

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.

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

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.

Insignificant.

5% is insignificant.

5% less energy will have an insignificant impact on the MOV's life span.
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.

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

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?

True, but 5% less energy will have no significant impact.

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.

- Franc Zabkar

--
Please remove one 'i' from my address when replying by email.
Reply to
Franc Zabkar

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.

Reply to
w_tom

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.? "

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.

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 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?

w_ can not grasp what Franc is saying.

If you want reliable information on surges and surge protection read:

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- 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:

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

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.

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.

-- bud--

Reply to
bud--

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:

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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.

Reply to
w_tom

On Tue, 24 Jul 2007 09:02:39 -0700, w_tom put finger to keyboard and composed:

A reduction of 3% (your numbers) is insignificant.

E = Vp x Ip x dt for *all* shunt mode protectors.

What will happen if you place a wire across a mains supply?

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

Earthing is irrelevant to a shunt mode system, unless the surge/spike is being shunted to earth.

Energy does *not* pass mysteriously through a MOV on its way to earth.

Explain how a shunt mode protector (eg transorb) connected across the generator terminals in an airplane utilises an earth connection?

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.

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.

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.

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%.

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

--
Please remove one 'i' from my address when replying by email.
Reply to
Franc Zabkar

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

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).

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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 religious belief in earthing - #3.

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?

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 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?

-- bud--

Reply to
bud--

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