Post by bud--Post by t***@optonline.netIf plug-ins are incapable of any protection because they have no
direct earth ground, how is it that the same components used in plug-
in surge suppressors are typically used to provide surge protection
inside appliances and electronics?
Again I answer - and you will ignore it. Those MOV once were in
appliances. No longer.
Bullcrap.
Bullcrap X 2. I was giving Tom the benefit of ignoring his silly
reply made months ago where his non-answer to the question was to
claim that MOVs are simply not used in appliances. I thought we were
past that, but obviously not. Of course, anyone that opens up most
modern day electronics and appliances knows they are.
And of course, Tom ignores the essential point of the question. And
that is that Tom has stated that appliances already contain surge
protection. Now, since he also claims that protection is impossible
without a direct connection to earth ground, how can that be?
Although we all know MOVs are widely used in this application, it
mattesr not a wit exactly what is used. The obvious contradiction
that Tom cannot escape is how can there be effective surge protection
inside appliances, with no earth ground?
Post by bud--trader4 showed in a previous thread that MOVs are widely used as
protection. w ignored it.
Yes indeed. Here it is again:
http://www.appliancedesign.com/CDA/Articles/Electronics/BNP_GUID_9-5-2006_A_10000000000000271505
Metal Oxide Varistors (MOVs) are typically used for transient over-
voltage suppression in AC line voltage applications. Lightning,
inductive load switching, or capacitor bank switching may cause
transient over-voltage conditions. In these applications, there also
exists the potential for a sustained abnormal over-voltage/limited-
current condition that may cause the MOV to go into thermal runaway,
resulting in overheating, out-gassing and possibly fire.
New thermally enhanced MOVs help protect a wide variety of low-power
systems against damage caused by over-current, over-temperature and
over-voltage faults, including lightning strikes, electrostatic
discharge (ESD) surges, loss of neutral, incorrect input voltage and
power induction.
These devices help provide protection in a wide range of AC line
applications, including AC mains LED lighting systems, PLC network
adapters, cell-phone chargers, AC/DC power supplies (up to 30 VA as
input power for 230 VAC input voltage), modem power supplies, AC panel
protection modules, AC power meters, and home appliances.
Here's another one, where a patent application discusses issues
associated with UL testing procedures on appliances that contain MOVs.
http://www.freshpatents.com/External-ground-connection-for-an-electrical-appliance-dt20081023ptan20080261419.php
BACKGROUND
As with many consumer products electrical appliances are subject to
rules, regulations, and laws which attempt to ensure product quality
and user safety. For example, UL 858 is a set of safety standards
which apply to electrically operated household cooking appliances such
as cooktops, ovens, stoves, ranges, etc. According to UL 858, a
household cooking appliance must pass a high potential voltage test
prior to being sold to a consumer. The high potential voltage test has
to be conducted after the household cooking appliance is fully
assembled. Unfortunately, implementing the high potential test can be
problematic because many cooking appliances include electrical
components which are designed to prevent voltages which fall in the
range of the test.
For example, many modern cooking appliances include one or more metal
oxide varistors (MOVs) on their power supplies to suppress high
voltage transients which can occur during power surges, lightning
storms, etc. To protect the cooking appliance and its user, the MOVs
prevent high input voltages such as those in the range of the required
high potential test. Cooking appliance manufacturers address this
problem by disconnecting the MOVs from a constant earth ground to
which the rest of the cooking appliance is connected. Without the
constant earth ground, the MOVs are able to float such that an
apparent voltage differential caused by the high potential input is
minimal. In traditional cooking appliances, connecting and/or
disconnecting the MOVs to the electrical ground requires that the
cooking appliance be disassembled
Post by bud--As an example, a GFCI outlet I recently took apart had an MOV for
protection. It connected only L-N.
Still not answered - how do the MOVs that ARE in equipment provide
protection when they do not have a good earth ground and "no earth
ground means no effective protection".
And still not answered - trader4's question "how is it that aircraft are
protected from surges from nearby lightning or direct strikes"?
Well, at least he just ignored that one instead of spewing total
nonsense.
Post by bud-- MOV is a diverting device.
MOVs are a clamping device. All they do is limit the voltage across
their terminals.
It does not stop and absorb energy as
bud claims.
Because the village idiot is unable to understand the simple explanation
of how plug-in suppressors work that is in the IEEE guide
and because the village idiot can't understand the explanation in a
Martzloff technical paper, which I summarized
the village idiot thinks plug-in suppressors work by stopping and absorbing.
We traced an MOV earthed a surge destructively through a
network of powered off computers.
You were not smart enough to RTFM. What a surprise.
The fact that Tom says MOVs are not used in appliances lays to rest
his claims about tracing much of anything. Anyone who has done any
tracing, repair, etc surely knows what an MOV looks like and that they
are common in modern appliances and electronics.
Post by bud-- Numerous sources say the same thing. MOVs protectors are not
effective when disconnected from protection
Numerous sources say the same thing - plug-in suppressors are effective.
The IEEE.
The NIST.
Martzloff in numerous technical papers.
Almost all of w's "responsible companies".
Here, for anyone just joining us, is what one of those responsible
companies, Siemens, has to say about plug-in surge protectors.
Siemens is probably the largest manufacturer in the world of every
kind of electric equipment, from dishwashers, to telecom, to the
largest power plant equipment:
http://www2.sea.siemens.com/Products/Residential-Electrical/Product/Surge-Protection/
Protection at the point of use
The second line of defense is the point of use. Here, homeowners can
reinforce point-of-entry protection by installing plug-in surge
protectors (strips) into grounded wall receptacles where sensitive
electronic equipment is located. These plug-in protectors, which
generally have much lower limiting voltages than entry protectors,
defend against externally and internally generated surges that travel
through power, phone, data, and coaxial lines. Plug-in power strips
should minimally include AC power protection and appropriate signal
line protection and should protect against both catastrophic and small
surges. These devices should be installed wherever expensive or
sensitive electronic equipment like computers, VCRs, fax machines, PCs
with modems, satellite systems, stereo systems, copiers and scanners
are located. All types of equipment with signal lines, such as phones,
cable TV, and satellites should be equipped with multi-port
protectors, which protect signal and AC lines.
Post by bud--Where is *any* source that says plug-in suppressors do NOT work? There
are none.
There is just w and his religious belief in earthing.
As the NIST says
Plug-in suppressors are "the easiest solution".
And "one effective solution is to have the consumer install" a multiport
plug-in suppressor.
Only ineffective protectors make that ‘stop and absorb’ claim
Only w makes a "stop and absorb" claim.
So that protection inside every
appliance is not overwhelmed.
Still missing - a source that say protection is "inside every appliance".
And missing - an explanation of the protection.
No earth ground means no effective
A protector is
only as effective as its earth ground
And the religious mantras that protect poor w from reality.
Surprise - surprise - still no source that agrees with w that plug-in
suppressors do NOT work.
- 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"?
- Why does the NIST guide say "One effective solution is to have the
consumer install" a multiport plug-in suppressor?
- How would a service panel suppressor provide any protection in the
IEEE example, pdf page 42?
- Why does the IEEE guide say for distant service points "the only
effective way of protecting the equipment is to use a multiport
[plug-in] protector"?
- Why did Martzloff say in his paper "One solution. illustrated in this
paper, is the insertion of a properly designed [multiport plug-in surge
suppressor]"?
- Why do your "responsible manufacturers" make plug-in suppressors?
- Why does "responsible" manufacturer SquareD says "electronic
equipment may need additional protection by installing plug-in
[suppressors] at the point of use"?
- Where is a source that says protection is "inside every appliance"?
- How do you protect airplanes from direct lightning strikes? Do they
drag an earthing chain?
Why can't you answer simple questions w???
For real science read the IEEE and NIST guides. Both say plug-in
suppressors are effective.
--
bud--