ABC Inventors - electrical safety device

[Ross Herbert]

Here is a response from the inventor which to my mind doesn't really
clarify things too much. With reference to point 6, I think he means
that it will isolate the power when a 6mA fault current flows.

On the Protectelect website www.protectelec.com.au the information is
very vague and confusing.

Ross H


QUOTE
Wayne Callen: Protex Switching Technology
Thanks to everyone for their comments, it is great to have an open
debate about electrical safety!

Firstly, the Protex Switching Technology is revolutionary! It is not a
safety switch, it references off the Neutral rather than the earth.
Protex detects voltages that should not be present on a conductive
surface.

I am an electrician & I appreciate how valuable safety switches are.
The Protex is simply the next step to improve electrical safety.

Let me take a minute to define exactly what it is that makes Protex
Unique:
1. It has very minimal moving parts
2. References off the Neutral
3. Protex does not use power until a fault is detected
4. It totally isolates (So yes if I accidentally drop an appliance in
the bath I will be completely protected with Protex & more
revolutionary my appliance will be ok & good to use again too.)
5. No earth this means that it can be fitted into everything
electrical. That means the PST will protect DC as well as AC
equipment.
6. It isolates the power in 6 milliamps, I think anyone who has every
received a shock would agree the less amps the better.
7. It is exceptionally fast cutting the power in less than
10milliseconds, protecting you & your equipment from damage
8. Because it does not generate heat it can be encapsulated and used
in dangerous & wet environments.
9. It is small & lightweight meaning it can be manufactured into
appliances of all sizes
10. Probably best of all it will be very cheap to manufacture

For me, any opportunity to increase safety and prevent electrical
injury is a great one. Please take the time to view our website [edit]
Feel free to submit questions to us directly through the site.

Thank you all for your thoughts & thank you to the ABC for the
opportunity to discuss Protex in an open forum.

 

[Phil Allison]

"Ross Herbert"

Here is a response from the inventor which to my mind doesn't really
clarify things too much.

** It makes them even more mysterious.

With reference to point 6, I think he means
that it will isolate the power when a 6mA fault current flows.

** That bit worries me a LOT.

On the Protectelect website www.protectelec.com.au the information is
very vague and confusing.


QUOTE
Wayne Callen: Protex Switching Technology
Thanks to everyone for their comments, it is great to have an open
debate about electrical safety!

Firstly, the Protex Switching Technology is revolutionary! It is not a
safety switch, it references off the Neutral rather than the earth.
Protex detects voltages that should not be present on a conductive
surface.

I am an electrician & I appreciate how valuable safety switches are.
The Protex is simply the next step to improve electrical safety.

Let me take a minute to define exactly what it is that makes Protex
Unique:
1. It has very minimal moving parts
2. References off the Neutral
3. Protex does not use power until a fault is detected
4. It totally isolates (So yes if I accidentally drop an appliance in
the bath I will be completely protected with Protex & more
revolutionary my appliance will be ok & good to use again too.)
5. No earth this means that it can be fitted into everything
electrical. That means the PST will protect DC as well as AC
equipment.
6. It isolates the power in 6 milliamps, I think anyone who has every
received a shock would agree the less amps the better.
7. It is exceptionally fast cutting the power in less than
10milliseconds, protecting you & your equipment from damage
8. Because it does not generate heat it can be encapsulated and used
in dangerous & wet environments.
9. It is small & lightweight meaning it can be manufactured into
appliances of all sizes
10. Probably best of all it will be very cheap to manufacture

For me, any opportunity to increase safety and prevent electrical
injury is a great one. Please take the time to view our website [edit]
Feel free to submit questions to us directly through the site.

** The device is alleged to sense voltage on conductive surfaces that are
NOT part of the AC circuitry - but is this in fact the exposed metalwork
or not ??? AFAIK the inventor has never made this point clear.

I suggested earlier that internal, non live metalwork ( or maybe some
deliberately added metalwork) could be used to sense if the appliance has
become wet.

I now suggest that this is the ONLY way the Protex could be designed and NOT
break the rules governing Class 2 - since one cannot connect anything to
exposed metalwork other than a Y2 capacitor of low value ( 10 nF).

Until the inventor has a prototype device, installed in an appliance,
approved by a registered approvals testing lab he has nothing more than a
cute idea that cannot be sold to anyone.




........... Phil

 

[Ross Herbert]

"Ross Herbert"


** It makes them even more mysterious.



** That bit worries me a LOT.

It concerned me a little as well.

On the Protectelect website www.protectelec.com.au the information is
very vague and confusing.


QUOTE
Wayne Callen: Protex Switching Technology
Thanks to everyone for their comments, it is great to have an open
debate about electrical safety!

Firstly, the Protex Switching Technology is revolutionary! It is not a
safety switch, it references off the Neutral rather than the earth.
Protex detects voltages that should not be present on a conductive
surface.

I am an electrician & I appreciate how valuable safety switches are.
The Protex is simply the next step to improve electrical safety.

Let me take a minute to define exactly what it is that makes Protex
Unique:
1. It has very minimal moving parts
2. References off the Neutral
3. Protex does not use power until a fault is detected
4. It totally isolates (So yes if I accidentally drop an appliance in
the bath I will be completely protected with Protex & more
revolutionary my appliance will be ok & good to use again too.)
5. No earth this means that it can be fitted into everything
electrical. That means the PST will protect DC as well as AC
equipment.
6. It isolates the power in 6 milliamps, I think anyone who has every
received a shock would agree the less amps the better.
7. It is exceptionally fast cutting the power in less than
10milliseconds, protecting you & your equipment from damage
8. Because it does not generate heat it can be encapsulated and used
in dangerous & wet environments.
9. It is small & lightweight meaning it can be manufactured into
appliances of all sizes
10. Probably best of all it will be very cheap to manufacture

For me, any opportunity to increase safety and prevent electrical
injury is a great one. Please take the time to view our website [edit]
Feel free to submit questions to us directly through the site.

** The device is alleged to sense voltage on conductive surfaces that are
NOT part of the AC circuitry - but is this in fact the exposed metalwork
or not ??? AFAIK the inventor has never made this point clear.

I suggested earlier that internal, non live metalwork ( or maybe some
deliberately added metalwork) could be used to sense if the appliance has
become wet.

Yes you did, and I was agreeing with you.

I now suggest that this is the ONLY way the Protex could be designed and NOT
break the rules governing Class 2 - since one cannot connect anything to
exposed metalwork other than a Y2 capacitor of low value ( 10 nF).

Until the inventor has a prototype device, installed in an appliance,
approved by a registered approvals testing lab he has nothing more than a
cute idea that cannot be sold to anyone.

Exactly.

At the moment, I can't see the manufacturers of conventional RCD's or
Line Isolation Overload Monitor equipment (or simply, LIM), as used in
hospital theatre ac supplies, will be quaking in their boots at the
prospect of Protex making their systems obsolete.

 

[Phil Allison]

"Ross Herbert"

At the moment, I can't see the manufacturers of conventional RCD's or
Line Isolation Overload Monitor equipment (or simply, LIM), as used in
hospital theatre ac supplies, will be quaking in their boots at the
prospect of Protex making their systems obsolete.

** Red herrings and irrelevant straw men are indeed your speciality.





............ Phil

 

[Ross Herbert]

"Ross Herbert"




** Red herrings and irrelevant straw men are indeed your speciality.

Phil,

I note that you conveniently snipped all of your own text to which I
was responding so that the relevance of your accusation against me is
missing. I believe you have vilified others in this forum who have
done the same when responding to your posts.

I think you misunderstand the difference between a "strawman argument"
and a simple statement which "expresses an opinion".

FYI, a strawman argument is a statement a person makes if they want to
attack an opposing position.

I simply made a statement (that part fits the definition at least)
expressing my opinion that I do not foresee Protex superseding
existing approved equipment designed to reduce shock hazard from ac
mains supplies anywhere in the near future.

Can you tell me, with regard to Protex, exactly how my statement of
opinion is making any argument at all? Furthermore, how was my
statement in any way attacking your "position", which BTW, I am not
"opposed" to?

I thought I was essentially in agreement with your assessment of
Protex, and not in opposition to that assessment.

 

[Phil Allison]

"Ross Herbert"
"Phil Allison"

I note that you conveniently snipped all of your own text to which I
was responding so that the relevance of your accusation against me is
missing.

** That straw man of yours stands alone and in isolation to any other
words.

FYI, a strawman argument is a statement a person makes if they want to
attack an opposing position.

** IMO - a "straw man" is an irrelevance put up merely because the author
knows it is easy to knock down and that readers will do that without any
additional persuasion.

It usually has some vague, allegorical connection to the issue - as yours
did.

But ultimately its effect is to muddy the water.

Can you tell me, with regard to Protex, exactly how my statement of
opinion is making any argument at all?

** It was a pure "straw man" - ie nothing to do with the original issue.

Lots of folk who post on NGs **love* to use them to confound discussions,
big note themselves and send the debate off in a new direction they have
chosen and want it to go.

I just get tired of seeing so many of them.




............ Phil

 

[Ross Herbert]

"Ross Herbert"
"Phil Allison"


** That straw man of yours stands alone and in isolation to any other
words.




** IMO - a "straw man" is an irrelevance put up merely because the author
knows it is easy to knock down and that readers will do that without any
additional persuasion.

Let's get things straight. By accusing me of setting up a "straw man"
you are in fact falsely attributing my expressed opinion as making an
argument (or stating a position) purporting to be factual. You did
this in order to get me to respond so that you could attack me. I
think that you have added a new technique to the list of definitions
of what constitures a "straw man".

http://encyclopedia.laborlawtalk.com/Straw_man

3. Present a misrepresentation of the opponent's position, refute it,
and pretend that the opponent's actual position has been refuted.

You have modified the technique in point 3 by adding an intermediate
step as follows;

What you did by accusing me of setting up a straw man was to
misrepresent my position in what was nothing more than an expressed
opinion, thus provoking a response which then allowed you to attack my
opinion and refute it as if I had presented it as a factual argument
in the first place.

If ever anyone was guilty of setting up a "straw man" this surely
proves it is you who is the transgressor. It is clear from your
responses below which shows this to be the case.

It usually has some vague, allegorical connection to the issue - as yours
did.

But ultimately its effect is to muddy the water.

An expressed opinion is simply one person's belief of what may occur.
You can either agree or disagree with an expressed opinion but you
have attributed that opinion as being a factual argument. It is clear
that you have falsely attributed my expressed opinion as a factual
argument because you now refute it as "vague" and making only an
"allegorical connection" with the subject under discussion.

Your new technique essentially conforms with that in point 3 of the
list of techniques.

** It was a pure "straw man" - ie nothing to do with the original issue.

Again, this response shows that you have falsely attributed my
expressed opinion as putting my position as a factual argument when it
did nothing of the sort. My expressed opinion was clearly associated
with the original issue.

Lots of folk who post on NGs **love* to use them to confound discussions,
big note themselves and send the debate off in a new direction they have
chosen and want it to go.

I just get tired of seeing so many of them.

You are now resorting to accusation by inference. By associating this
particular discussion between you and myself, with the generalisation
"lots of folk" etc. etc., you are including me in that nebulous group,
"lots of folk". Having now established the fact that I am included in
that group you then proceed to denigrate them. You then issue the coup
de gras by portraying your case as factual by stating "I just get
tired of seeing so many of them."

Boy, are you a sneaky buggeer or what?

For those who don't want to follow the link above;

Definition of Straw Man:

The straw-man rhetorical technique is a the practice of refuting
weaker arguments than one's opponents actually offer. To "set up a
straw man" or "set up a straw-man argument" is to create a position
that is easy to refute, then attribute that position to your opponent.

One can set up a straw man in several different ways:

1. Present only a portion of the opponent's arguments (often a weak
one), refute it, and pretend that all of their arguments have been
refuted.

2. Present the opponent's argument in weakened form, refute it, and
pretend that the original has been refuted.

3. Present a misrepresentation of the opponent's position, refute it,
and pretend that the opponent's actual position has been refuted.

4. Present someone who defends a position poorly as the defender,
refute their arguments, and pretend that every argument for that
position has been refuted.

5. Invent a fictitious persona with actions or beliefs that are
criticised, and pretend that that person represents a group that the
speaker is critical of.

Some logic textbooks define the straw-man fallacy only as a
misrepresented argument. It is now common, however, to use the term to
refer to all of these tactics. The straw-man technique is also used as
a form of media manipulation.

Why my expressed opinion cannot possibly be interpreted as a straw man
when referred to above 5 definitions:

** You made no argument in any part of your response to my original
post and I did not attribute any claim as being your own so there was
nothing for me to refute.

** I did not misrepresent anything you wrote in response to my
original post. In fact I agreed with your position.

** I did not present anyone or invent a fictitious persona whose
beliefs I was planning to criticise.

** My expressed opinion does not even fit the more liberal
description of being a "misrepresented argument" because there was no
argument in it at all. Also, my expressed opinion could hardly have
been interpreted as being an attempt at "media manipulation" either,
so when all is said and done Phil, you just like to make wild
accusations whenever it suits you.

 

[Chris]

Let's get things straight. By accusing me of setting up a "straw man"
you are in fact falsely attributing my expressed opinion as making an
argument (or stating a position) purporting to be factual. You did
this in order to get me to respond so that you could attack me. I
think that you have added a new technique to the list of definitions
of what constitures a "straw man".

http://encyclopedia.laborlawtalk.com/Straw_man

3. Present a misrepresentation of the opponent's position, refute it,
and pretend that the opponent's actual position has been refuted.

You have modified the technique in point 3 by adding an intermediate
step as follows;

What you did by accusing me of setting up a straw man was to
misrepresent my position in what was nothing more than an expressed
opinion, thus provoking a response which then allowed you to attack my
opinion and refute it as if I had presented it as a factual argument
in the first place.

If ever anyone was guilty of setting up a "straw man" this surely
proves it is you who is the transgressor. It is clear from your
responses below which shows this to be the case.


An expressed opinion is simply one person's belief of what may occur.
You can either agree or disagree with an expressed opinion but you
have attributed that opinion as being a factual argument. It is clear
that you have falsely attributed my expressed opinion as a factual
argument because you now refute it as "vague" and making only an
"allegorical connection" with the subject under discussion.

Your new technique essentially conforms with that in point 3 of the
list of techniques.


Again, this response shows that you have falsely attributed my
expressed opinion as putting my position as a factual argument when it
did nothing of the sort. My expressed opinion was clearly associated
with the original issue.


You are now resorting to accusation by inference. By associating this
particular discussion between you and myself, with the generalisation
"lots of folk" etc. etc., you are including me in that nebulous group,
"lots of folk". Having now established the fact that I am included in
that group you then proceed to denigrate them. You then issue the coup
de gras by portraying your case as factual by stating "I just get
tired of seeing so many of them."

Boy, are you a sneaky buggeer or what?

For those who don't want to follow the link above;

Definition of Straw Man:

The straw-man rhetorical technique is a the practice of refuting
weaker arguments than one's opponents actually offer. To "set up a
straw man" or "set up a straw-man argument" is to create a position
that is easy to refute, then attribute that position to your opponent.

One can set up a straw man in several different ways:

1. Present only a portion of the opponent's arguments (often a weak
one), refute it, and pretend that all of their arguments have been
refuted.

2. Present the opponent's argument in weakened form, refute it, and
pretend that the original has been refuted.

3. Present a misrepresentation of the opponent's position, refute it,
and pretend that the opponent's actual position has been refuted.

4. Present someone who defends a position poorly as the defender,
refute their arguments, and pretend that every argument for that
position has been refuted.

5. Invent a fictitious persona with actions or beliefs that are
criticised, and pretend that that person represents a group that the
speaker is critical of.

Some logic textbooks define the straw-man fallacy only as a
misrepresented argument. It is now common, however, to use the term to
refer to all of these tactics. The straw-man technique is also used as
a form of media manipulation.

Why my expressed opinion cannot possibly be interpreted as a straw man
when referred to above 5 definitions:

** You made no argument in any part of your response to my original
post and I did not attribute any claim as being your own so there was
nothing for me to refute.

** I did not misrepresent anything you wrote in response to my
original post. In fact I agreed with your position.

** I did not present anyone or invent a fictitious persona whose
beliefs I was planning to criticise.

** My expressed opinion does not even fit the more liberal
description of being a "misrepresented argument" because there was no
argument in it at all. Also, my expressed opinion could hardly have
been interpreted as being an attempt at "media manipulation" either,
so when all is said and done Phil, you just like to make wild
accusations whenever it suits you.

Hi Ross,

Do what just about everyone else does here - ignore him - read his stupid
dribblings if you have to but never respond - he is a vile creature! The
sooner he leaves this group the better and then it will get to where it
should be with kind considerate people like yourself helping others. This is
one of the worst NG's around thanks to the likes of him - just look at some
of his recent posts.

He chastises someone in "Which is better electric or blade" cause they
should note that as OT yet he posts "Poxy is Homophobic" without the "OT".
What has homophobic got to do with electronics?? The guy is a complete
mental wasteland.

Forget it - move on - spend the time going for a walk in the park.

Cheers.

 

[Ross Herbert]

Hi Ross,

Do what just about everyone else does here - ignore him - read his stupid
dribblings if you have to but never respond - he is a vile creature! The
sooner he leaves this group the better and then it will get to where it
should be with kind considerate people like yourself helping others. This is
one of the worst NG's around thanks to the likes of him - just look at some
of his recent posts.

He chastises someone in "Which is better electric or blade" cause they
should note that as OT yet he posts "Poxy is Homophobic" without the "OT".
What has homophobic got to do with electronics?? The guy is a complete
mental wasteland.

Forget it - move on - spend the time going for a walk in the park.

Cheers.

Hi Chris,

Believe me, I tried hard not to get involved with Phil on this one. In
the distant past Phil engaged in some vilification of me in his posts
and we both came to an agreement that we would not respond to each
other's posts. That has lasted at least 12 months I think.

If you check the thread you will see that I responded to the OP and
then Phil broke our agreement and responded directly to mine and since
he was sounding reasonable I replied. It was all a ruse to suck me in
so that he could get stuck in to me once more. I think he is finding
it difficult to get a good rational argument lately and he has to
resort to vilification, denigration and bad mouthing people much
sooner than he normally does, while at the same time trying to turn
the blame and excuse his own bad behaviour. I must admit that so far
he hasn't actually started in with the foul mouthing as yet, so here's
hoping....

I promise I won't respond any further to Phil's provocation.

Cheers.

 

[Chris]

Hi Chris,

Believe me, I tried hard not to get involved with Phil on this one. In
the distant past Phil engaged in some vilification of me in his posts
and we both came to an agreement that we would not respond to each
other's posts. That has lasted at least 12 months I think.

If you check the thread you will see that I responded to the OP and
then Phil broke our agreement and responded directly to mine and since
he was sounding reasonable I replied. It was all a ruse to suck me in
so that he could get stuck in to me once more. I think he is finding
it difficult to get a good rational argument lately and he has to
resort to vilification, denigration and bad mouthing people much
sooner than he normally does, while at the same time trying to turn
the blame and excuse his own bad behaviour. I must admit that so far
he hasn't actually started in with the foul mouthing as yet, so here's
hoping....

I promise I won't respond any further to Phil's provocation.

Cheers.

Good on You!

Cheers.

 

[Phil Allison]

"Ross Herbert"


( snip an enormous pile a paranoid crapola)


** Kindly go and get stuffed.

Do not pass go - do visit a psychiatrist on the way.




........... Phil

 

[David L. Jones]

Did anybody see the New Inventors last night? Can anyone guess how
"Protex Switching Technology" works? The inventor said something about
detecting voltage changes, and using the neutral as the reference.

See http://www.abc.net.au/newinventors/txt/s1356442.htm


- Franc Zabkar

The Australian Patent application abstract can be found here:
http://apa.hpa.com.au:8080/ipapa/iv_pdf?report=ipapa&index=1&doc=1461438

and the full patent can be downloaded here for a small fee:
http://free.patentfetcher.com/GetPatentPDF.php?f=Pubs/WO/20/04/WO2004013943.pdf

I have a copy already downloaded if anyone is interested.

Dave

 

[David L. Jones]

The Australian Patent application abstract can be found here:
http://apa.hpa.com.au:8080/ipapa/iv_pdf?report=ipapa&index=1&doc=1461438

and the full patent can be downloaded here for a small fee:
http://free.patentfetcher.com/GetPatentPDF.php?f=Pubs/WO/20/04/WO2004013943.pdf

I have a copy already downloaded if anyone is interested.

Dave

Also, for the full patent try here:
http://www.wipo.int/ipdl/IPDL-CIMAGES/images3.jsp?WEEK=07/2004&DOC=04/013943&TYPE=A1&TIME=1116214802

Dave

 

[Phil Allison]

"David L. Jones"

Also, for the full patent try here:
http://www.wipo.int/ipdl/IPDL-CIMAGES/images3.jsp?WEEK=07/2004&DOC=04/013943&TYPE=A1&TIME=1116214802

** Oh dear.

Beware of electricians from Newcastle.



............ Phil

 

[David L. Jones]

"David L. Jones"

http://www.wipo.int/ipdl/IPDL-CIMAGES/images3.jsp?WEEK=07/2004&DOC=04/013943&TYPE=A1&TIME=1116214802



** Oh dear.

Beware of electricians from Newcastle.



........... Phil

You gotta love patents.
He could have kept all the secrets to himself and potted the whole
thing, and no one would know how it works.
Now, many $$$$$ later, it's all there for the world to see.

Dave

 

[Phil Allison]

"David L. Jones"

You gotta love patents.

** It is only a patent application far as I can see.

That idea does not seem nearly novel enough to deserve a patent.

He could have kept all the secrets to himself and potted the whole
thing, and no one would know how it works.

** Madness - the only way any such device ( IF it worked and was and
legal to install ) could be commercially exploited is to try and get it
covered by world wide patents, then sell the rights to a manufacturer in
Asia.


This POS looks like a total non-starter to me.




............. Phil

 

[KLR]

Also, for the full patent try here:
http://www.wipo.int/ipdl/IPDL-CIMAGES/images3.jsp?WEEK=07/2004&DOC=04/013943&TYPE=A1&TIME=1116214802

Dave

The fact that you are using relays - and 2 relays have to activate -
one after the other to kill the power - significantly delaying the
breaking time of the circuit, you have 2 relay coils there - each
240v, which means fine wire - which means fragile - and even worse
being in a bathroom or kitchen appliance (wet area) where there is
steam, heat and condensation to increase the risk the fine coil wire
will corrode and fail.

If EITHER of these 240v relay coils goes open circuit - the protection
is defeated and there is no fail-safe mechanism or prior warning of
this failure to the user.

Also if someone comes into contact with both the active and neutral
simultaneously (the same scenario that an RCD wont protect you if on
and insulated floor), this device wont do anything to help protect
either. In fact - with the absence of an earth - NOTHING WILL - short
of an isolation transformer that can only provide around 30ma or less,
and this may even be fatal if connected to the body continuously for
any length of time !

With a hair dryer - or other appliance at risk of being immersed, the
protective internal shield would have to cover a large area inside the
dryer - fully encasing the area around the switch, the element, motor
any bare connections to ensure no part of the dryer could be dunked
without this "protective shield" area coming into contact with the
water BEFORE the mains connection came into contact with the water.

This module would then have to be totally waterproofed, as well as its
reset/test buttons (if needed), and incoming mains cord as after it
activated, the primary side of the relay would still be live and would
possibly also be underwater.

-------------------------------------

If you were going to go to all this trouble, you would be better off
just having an earth wire inside the appliance (say hair dryer etc) to
part 17 (the conductive housing) and use a 3 pin cord and plug -
allowing the RCD to do its job with some certainty.

If you had no RCD, then you wouldn't be any less safe than with a 2
pin cord attatched to the unit.


If you still wanted the outer appliance case insulated from earth for
greater safety, this earthed area could still be inside and not
touchable from the outside.
This would cost a hell of a lot less than building up all this - and
then having to have the internal conductive housing anyway - to act as
a trigger for this proposed device.


This is before we even start discussing the use of relays with mains
rated contacts of a sufficient current for conditions such as the load
short circuiting, possible surge currents when starting etc etc.




Somehow I dont see all this being done for a dollar.
And in this cost-conscious world we now live in - I can't see this
being fitted to any cheap consumer goods, unless it was legislated,
and I doubt that that is ever gonna happen here.

 

[Franc Zabkar]

Also, for the full patent try here:
http://www.wipo.int/ipdl/IPDL-CIMAGES/images3.jsp?WEEK=07/2004&DOC=04/013943&TYPE=A1&TIME=1116214802

Dave

I'm not familiar with the relevant standard, but can this device
possibly meet the requirements for isolation between housing and
neutral? Furthermore, if the active and neutral conductors are
reversed in the GPO or in an extension cord, wouldn't the device
itself render the appliance unsafe? Granted, Protex may interrupt
power to the appliance in this case, but current (6mA?) would need to
pass through the user's body in order for it to do so. Elsewhere in
the patent application I see a design variation incorporating an
optocoupler. Perhaps that is a better approach.


- Franc Zabkar

 

[Ross Herbert]

Also, for the full patent try here:
http://www.wipo.int/ipdl/IPDL-CIMAGES/images3.jsp?WEEK=07/2004&DOC=04/013943&TYPE=A1&TIME=1116214802

Dave

The circuit arrangement looks to me to perform a similar task to that
described for the voltage dependant ELCB as described by Pat Ward. The
main difference seems to be that the vELCB used a ground referenced
metal frame and Protex uses a neutral referenced metal part(17).

QUOTE:
ELCB = Earth Leakage Circuit Breaker. There are two types of ELCB, the
voltage operated device and the differential current operated device.
For the convenience of this article only (and at the risk of causing
even more confusion) I will refer to these as vELCB and iELCB. vELCBs
were first introduced about sixty years ago and iELCBs were first
introduced about forty years ago.

The principle of operation of the vELCB is as follows. Under normal
conditions the closed contacts of the vELCB feed the supply current to
the load. The load is protected by a metal frame, such as in an
electric cooker. The vELCB also has a relay coil, one end of which is
connected to the metal frame and one end connected directly to ground.
A shock risk will arise if a breakdown in the insulation occurs in the
load which causes the metal frame to rise to a voltage above earth. A
resultant current will flow from the metalwork through the relay coil
to earth and when the frame voltage reaches a dangerous level, e.g. 50
volts, the current flowing through the relay coil will be sufficient
to activate the relay thereby causing opening of the supply contacts
and removal of the shock risk.

As can be seen from the above description, this type of ELCB is
essentially a voltage sensing device intended to detect dangerous
touch voltages. The level of shock protection provided by the vELCB
was somewhat limited as these devices would not provide shock
protection in the event of direct contact with a live part. An
additional problem with the vELCB was its tendency to be tripped by
earth currents originating in other installations.

Pat Ward is managing director of Western Automation R & D based in
Ballinasloe. The company is a specialist designer and manufacturer of
RCD products. Pat has been an active member of technical committees in
ETCI, IEC and CENELEC since 1991 and has been involved in the drafting
of several international standards for RCD & RCMs. He has also
participated in working groups within IEC addressing problems of
reliability and EMC requirements for RCDs.


The full article is here
http://www.westernautomation.com/pages/demystify.htm

 

[David L. Jones]

The circuit arrangement looks to me to perform a similar task to that
described for the voltage dependant ELCB as described by Pat Ward. The
main difference seems to be that the vELCB used a ground referenced
metal frame and Protex uses a neutral referenced metal part(17).

QUOTE:
ELCB = Earth Leakage Circuit Breaker. There are two types of ELCB, the
voltage operated device and the differential current operated device.
For the convenience of this article only (and at the risk of causing
even more confusion) I will refer to these as vELCB and iELCB. vELCBs
were first introduced about sixty years ago and iELCBs were first
introduced about forty years ago.

The principle of operation of the vELCB is as follows. Under normal
conditions the closed contacts of the vELCB feed the supply current to
the load. The load is protected by a metal frame, such as in an
electric cooker. The vELCB also has a relay coil, one end of which is
connected to the metal frame and one end connected directly to ground.
A shock risk will arise if a breakdown in the insulation occurs in the
load which causes the metal frame to rise to a voltage above earth. A
resultant current will flow from the metalwork through the relay coil
to earth and when the frame voltage reaches a dangerous level, e.g. 50
volts, the current flowing through the relay coil will be sufficient
to activate the relay thereby causing opening of the supply contacts
and removal of the shock risk.

As can be seen from the above description, this type of ELCB is
essentially a voltage sensing device intended to detect dangerous
touch voltages. The level of shock protection provided by the vELCB
was somewhat limited as these devices would not provide shock
protection in the event of direct contact with a live part. An
additional problem with the vELCB was its tendency to be tripped by
earth currents originating in other installations.

Pat Ward is managing director of Western Automation R & D based in
Ballinasloe. The company is a specialist designer and manufacturer of
RCD products. Pat has been an active member of technical committees in
ETCI, IEC and CENELEC since 1991 and has been involved in the drafting
of several international standards for RCD & RCMs. He has also
participated in working groups within IEC addressing problems of
reliability and EMC requirements for RCDs.


The full article is here
http://www.westernautomation.com/pages/demystify.htm

Hi Ross,
Any reason why you have set your posts to be not archived?
They are useful and it would be nice to have them archived on Google.

Regards
Dave