isolation transformer needed

[sparky]

On Jan 2, 8:15 am, "Dave Plowman (News)" <d...@davenoise.co.uk> wrote:

In article <postings-27DDC5.17183701012...@news.bigpond.com>,
   David <posti...@REMOVE-TO-REPLYconfidential-counselling.com> wrote:

No it hasn't. Isolation transformers are still used for many safety
related reasons. But don't expect you to understand why. Obviously.
I am one of those who rarely agree with Phil, but this time he is giving
you the right info.
From your post Dave it does seem you do not understand the reasons
behind the use of isolation xformers when working on or testing gear.

Seems to me some expect the use of an isolation transformer to be some
form of magic bullet that removes all risks. It doesn't. But can reduce
the sort of risk caused by one side of a mains supply being grounded. If
you then ground one leg of the output of that transformer by any means you
are back to square one.
 However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Quite correct.
The isolation transformer is a great tool for the workbench if a
person knows how to utilize it. That appears to be the problem with
some posters here. They have either had no instructions about the use
of the isolation transformer on the service bench or they just ignore
any instruction they have had.

 

[Meat Plow]

On Sat, 2 Jan 2010 12:14:17 +1100, "Phil Allison"
<phil_a@tpg.com.au>wrote:

"Meat Head Moron "

"Phil Allison"


** Standard procedure for servicing any unit with an unknown fault is to
FIRST see what happens when plugged into a normal AC outlet - ie one
with
neutral and ground linked at the service box.

Funny that was never on any service literature or diagnostic procedure
documentation I ever read. Nor would I have ever made it my own
practice as a first step thinking back 30 through 30 years.


** My post does NOT say that it is the very first step.

It does say that with an unknown but possible PSU fault - connection to a
normal RCD protected AC outlet should be done FIRST - before using an
isolation tranny.

Obviously, visual inspection comes very first, including carefully checking
of the AC plug, lead and fuse if accessible. If the AC fuse is missing or
blown, then a major fault is likely.

In the latter case, MY procedure is to install a suitable new AC fuse and
gradually bring up the item using a variac - all the time monitoring the
current draw from the AC supply with meter specially built for that purpose.
If the AC current becomes unusually large ( or the RCD trips) as the AC
voltage rises - game over.



.... Phil

You wrote this?

"Standard procedure for servicing any unit with an unknown fault is to
FIRST"

I have 30+ years in commercial repair Phil. I have my own techniques
that I have stood in front of classes of electrical engineer students
and lectured upon.

My first usage if a variac dates back to the early 80's. However it
was an isolation variac designed for live chassis tv sets. Since most
of my work was warranty service we were required to do Hipot checks
as a final test. Nowhere do I recall ever needing to plug a set into a
GFI/RCD/RCCB to diagnose it.

 

[Ron]

On 02/01/2010 13:58, sparky wrote:

On Jan 2, 8:15 am, "Dave Plowman (News)"<d...@davenoise.co.uk> wrote:
In article<postings-27DDC5.17183701012...@news.bigpond.com>,
David<posti...@REMOVE-TO-REPLYconfidential-counselling.com> wrote:

No it hasn't. Isolation transformers are still used for many safety
related reasons. But don't expect you to understand why. Obviously.
I am one of those who rarely agree with Phil, but this time he is giving
you the right info.
From your post Dave it does seem you do not understand the reasons
behind the use of isolation xformers when working on or testing gear.

Seems to me some expect the use of an isolation transformer to be some
form of magic bullet that removes all risks. It doesn't. But can reduce
the sort of risk caused by one side of a mains supply being grounded. If
you then ground one leg of the output of that transformer by any means you
are back to square one.
However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.


Quite correct.
The isolation transformer is a great tool for the workbench if a
person knows how to utilize it. That appears to be the problem with
some posters here. They have either had no instructions about the use
of the isolation transformer on the service bench or they just ignore
any instruction they have had.

The golden rule when working on any kind of live gear, isolation tranny
or not, is to keep one hand in your pocket (but not too close to the
'spheres'

Ron

 

[Phil Allison]

"sparky"

Some total MORON

However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Quite correct.

** It is totally WRONG !!


The isolation transformer is a great tool for the workbench if a
person knows how to utilize it.

** Counts a clueless imbecile you out.



..... Phil

 

[Phil Allison]

Meat Head Moron "

"Phil Allison"

You wrote this?

"Standard procedure for servicing any unit with an unknown fault is to
FIRST"

** Only total FUCKHEADS take phases out of context like that.

Boy, oh boy, do YOU ever qualify as one of them.

I have 30+ years in commercial repair Phil. I have my own techniques
that I have stood in front of classes of electrical engineer students
and lectured upon.

** Nearly 40 years in my case.

My first usage if a variac dates back to the early 80's. However it
was an isolation variac designed for live chassis tv sets. Since most
of my work was warranty service we were required to do Hipot checks
as a final test. Nowhere do I recall ever needing to plug a set into a
GFI/RCD/RCCB to diagnose it.

** So what ??

You were doing it an unsafe way for 30 years.

Never to late to do it right.


...... Phil

 

[David]

In article <50d3511cf4dave@davenoise.co.uk>,
"Dave Plowman (News)" <dave@davenoise.co.uk> wrote:

In article <postings-27DDC5.17183701012010@news.bigpond.com>,
David <postings@REMOVE-TO-REPLYconfidential-counselling.com> wrote:
No it hasn't. Isolation transformers are still used for many safety
related reasons. But don't expect you to understand why. Obviously.

I am one of those who rarely agree with Phil, but this time he is giving
you the right info.

From your post Dave it does seem you do not understand the reasons
behind the use of isolation xformers when working on or testing gear.

Seems to me some expect the use of an isolation transformer to be some
form of magic bullet that removes all risks. It doesn't. But can reduce
the sort of risk caused by one side of a mains supply being grounded. If
you then ground one leg of the output of that transformer by any means you
are back to square one.
However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can. When they listen to someones advice that it is OK to
touch either side of the output of the xformer. As Phil pointed out if
there is a problem that could be lethal

David

 

[David Nebenzahl]

On 1/2/2010 4:19 PM David spake thus:

In article <50d3511cf4dave@davenoise.co.uk>,
"Dave Plowman (News)" <dave@davenoise.co.uk> wrote:

However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can. When they listen to someones advice that it is OK to
touch either side of the output of the xformer. As Phil pointed out if
there is a problem that could be lethal

That is in no way a fault of the isolation transformer. Might as well
blame power lines because some doofus, somewhere told someone that it's
OK to touch one side of the line.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"

 

[Phil Allison]

"David"

" Some pommy retard "

However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can. When they listen to someones advice that it is OK to
touch either side of the output of the xformer. As Phil pointed out if
there is a problem that could be lethal

** Aside from the above issue - the number one reason for NOT using an
isolation tranny as the usual supply of AC power on a workbench is that the
very same tech who has become oblivious to the danger of contacting live AC
wiring WILL at some future time and place find themselves working on
energised items WITHOUT the benefit of such isolation.

The DANGER is in the false impression of harmlessness that builds up in the
mind of the tech.

Old habits die hard - but electricity kills quick.



..... Phil

 

[Phil Allison]

"David Nebenzahl"
David spake thus:

"Dave Plowman (Nutcase)"

However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can. When they listen to someones advice that it is OK to
touch either side of the output of the xformer. As Phil pointed out if
there is a problem that could be lethal

That is in no way a fault of the isolation transformer.

** My god - you are one, fucking retarded MORON.



..... Phil

 

[Phil Allison]

"David"

" Some pommy retard "

However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can. When they listen to someones advice that it is OK to
touch either side of the output of the xformer. As Phil pointed out if
there is a problem that could be lethal

** Aside from the above issue - the number one reason for NOT using an
isolation tranny as the usual supply of AC power on a workbench is that the
very same tech who has become oblivious to the danger of contacting live AC
wiring WILL at some future time and place find themselves working on
energised items WITHOUT the benefit of such isolation.

The DANGER is in the false impression of harmlessness that builds up in the
mind of the tech.

Old habits die hard - but electricity kills quick.



..... Phil

 

[sparky]

On Jan 2, 7:39 pm, "Phil Allison" <phi...@tpg.com.au> wrote:

"David"

" Some pommy retard "

 However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can.  When they listen to someones advice that it is OK to
touch either side of the output of the xformer.  As Phil pointed out if
there is a problem that could be lethal

** Aside from the above issue -  the number one reason for  NOT using an
isolation tranny as the usual supply of AC power on a workbench is that the
very same tech who has become oblivious to the danger of contacting live AC
wiring  WILL  at some future time and place find themselves working on
energised items  WITHOUT  the benefit of such isolation.

The DANGER  is in the false impression of harmlessness that builds up in the
mind of the tech.

Old habits die hard -  but electricity kills quick.

....  Phil

An isolation transformer does not render an item harmless but it does
provide the technician with an extra tool to use during his work. As
with all things using high voltage common sense must be used. ---- -
- - A thing which seems seriously lacking in this news group.

 

[Michael A. Terrell]

Phil Allison wrote:

"David"

" Some pommy retard "

However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can. When they listen to someones advice that it is OK to
touch either side of the output of the xformer. As Phil pointed out if
there is a problem that could be lethal

** Aside from the above issue - the number one reason for NOT using an
isolation tranny as the usual supply of AC power on a workbench is that the
very same tech who has become oblivious to the danger of contacting live AC
wiring WILL at some future time and place find themselves working on
energised items WITHOUT the benefit of such isolation.

The DANGER is in the false impression of harmlessness that builds up in the
mind of the tech.

Old habits die hard - but electricity kills quick.

.... Phil

Then you should be dead by now.


--
Greed is the root of all eBay.

 

[Meat Plow]

On Sun, 3 Jan 2010 15:13:01 +1100, "Phil Allison"
<phil_a@tpg.com.au>wrote:

"David"

" Some pommy retard "

However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can. When they listen to someones advice that it is OK to
touch either side of the output of the xformer. As Phil pointed out if
there is a problem that could be lethal


** Aside from the above issue - the number one reason for NOT using an
isolation tranny as the usual supply of AC power on a workbench is that the
very same tech who has become oblivious to the danger of contacting live AC
wiring WILL at some future time and place find themselves working on
energised items WITHOUT the benefit of such isolation.

The DANGER is in the false impression of harmlessness that builds up in the
mind of the tech.

Old habits die hard - but electricity kills quick.

Becomeing complacent in or unconcerned with electrical hazards is a
fact of life (or death.) You're not going to save the world.

 

[Ron]

On 03/01/2010 15:51, sparky wrote:

On Jan 3, 10:48 am, Meat Plow<m...@petitmorte.net> wrote:
On Sun, 3 Jan 2010 15:13:01 +1100, "Phil Allison"
phi...@tpg.com.au>wrote:







"David"

" Some pommy retard"

However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can. When they listen to someones advice that it is OK to
touch either side of the output of the xformer. As Phil pointed out if
there is a problem that could be lethal

** Aside from the above issue - the number one reason for NOT using an
isolation tranny as the usual supply of AC power on a workbench is that the
very same tech who has become oblivious to the danger of contacting live AC
wiring WILL at some future time and place find themselves working on
energised items WITHOUT the benefit of such isolation.

The DANGER is in the false impression of harmlessness that builds up in the
mind of the tech.

Old habits die hard - but electricity kills quick.

Becomeing complacent in or unconcerned with electrical hazards is a
fact of life (or death.) You're not going to save the world.- Hide quoted text -

- Show quoted text -



Anyone using an isolation transformer should not become complacent.
It is a tool with hazards.
Just the same as using a power saw has hazards, but the hazards can be
minimized and the user must be vigilant.

An isolation transformer reduces the hazards, no one said it removes
them completely. It should be understood that anyone working on live
electrical equipment has the capacity to comprehend the dangers or is
otherwise advised to entrust the work to someone more competent.

To paraphrase Monty Python . "This thread is getting silly"

 

[sparky]

On Jan 3, 10:48 am, Meat Plow <m...@petitmorte.net> wrote:

On Sun, 3 Jan 2010 15:13:01 +1100, "Phil Allison"
phi...@tpg.com.au>wrote:







"David"

" Some pommy retard "

 However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

Well, I sure can.  When they listen to someones advice that it is OK to
touch either side of the output of the xformer.  As Phil pointed out if
there is a problem that could be lethal

** Aside from the above issue -  the number one reason for  NOT using an
isolation tranny as the usual supply of AC power on a workbench is that the
very same tech who has become oblivious to the danger of contacting live AC
wiring  WILL  at some future time and place find themselves working on
energised items  WITHOUT  the benefit of such isolation.

The DANGER  is in the false impression of harmlessness that builds up in the
mind of the tech.

Old habits die hard -  but electricity kills quick.

Becomeing complacent in or unconcerned with electrical hazards is a
fact of life (or death.) You're not going to save the world.- Hide quoted text -

- Show quoted text -

Anyone using an isolation transformer should not become complacent.
It is a tool with hazards.
Just the same as using a power saw has hazards, but the hazards can be
minimized and the user must be vigilant.

 

[John Robertson]

Dave Plowman (News) wrote:

In article <postings-27DDC5.17183701012010@news.bigpond.com>,
David <postings@REMOVE-TO-REPLYconfidential-counselling.com> wrote:
No it hasn't. Isolation transformers are still used for many safety
related reasons. But don't expect you to understand why. Obviously.

I am one of those who rarely agree with Phil, but this time he is giving
you the right info.

From your post Dave it does seem you do not understand the reasons
behind the use of isolation xformers when working on or testing gear.

Seems to me some expect the use of an isolation transformer to be some
form of magic bullet that removes all risks. It doesn't. But can reduce
the sort of risk caused by one side of a mains supply being grounded. If
you then ground one leg of the output of that transformer by any means you
are back to square one.
However, I can't think of any case where the use of an isolation
transformer *increases* any hazard.

How about the technician who assumes that the isolation transformer has
decreased the risk of shock and behaves accordingly...without verifying
mains isolation before reaching inside live equipment?

Assumptions can be quite shocking!

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[Phil Allison]

"Meathead Plonker"

Becomeing complacent in or unconcerned with electrical hazards is a
fact of life (or death.)

** Absolute BOLLOCKS it is.



..... Phil

 

[Phil Allison]

"sparky is a MORON "


** Fuck off

- you brainless PARROTING fuckwit !!



..... Phil

 

[GregS]

In article <wIn%m.696$XU.576@newsfe03.iad>, "Leonard Caillouet" <nospam@noway.com> wrote:

Please see page 2.

http://www.cbtricks.com/miscellaneous/tech_publications/scope/floating.pdf

I swear I have seen documented procedures lifting the ground of an oscilloscope.
I though it was Tektronix, but I don't remember the details.

I like using battery scopes and also differential probes.

greg

 

[GregS]

In article <3dhu1a.srn.17.9@news.alt.net>, Meat Plow <meat@petitmorte.net> wrote:

On Fri, 1 Jan 2010 12:22:41 +1100, "Phil Allison"
phil_a@tpg.com.au>wrote:

** Standard procedure for servicing any unit with an unknown fault is to
FIRST see what happens when plugged into a normal AC outlet - ie one with
neutral and ground linked at the service box.

Funny that was never on any service literature or diagnostic procedure
documentation I ever read. Nor would I have ever made it my own
practice as a first step thinking back 30 through 30 years.

But then again this is an internationally mirrored forum so I don't
really try to pawn off my particular service procedures as the gospel
where the diagnostics flow chart may be much different in certain
regions of the globe.

I have hooked things up with isolation and later found things like a motor short.
Works fine with the transformer.

I didn't always first check the customers explanation and plug something
in right away before doing anything, but I do it now.


greg