-Original Message-
From: POWELL, DOUG [ mailto:doug.pow...@aei.com]
Sent: Friday, May 23, 2003 3:57 PM
To: EMC-PSTC (E-mail)
Subject: Bad Fuse vs. Good Fuse
Hello all,
Recently, in my company, we've been discussing what exactly constitutes a good
or bad fuse. In this industry we
Hello all,
Recently, in my company, we've been discussing what exactly constitutes a good
or bad fuse. In this industry we often hear that the trouble with a defective
product was, the fuse was bad. I occurred to me that the fuse is not bad,
it performed exactly intended. In fact if the
Hi Richard:
is the below information true
for both the AC and DC hipot methods?
Some companies have contractors,subcontractors,
incoming and final hipot...
so it does and can occur at least 4 times,
before its shipped to a customer.
The theory says that the onset of the
I read in !emc-pstc that simon_...@emc.com wrote (in 277DD60FB639D511AC
0400b0d068b71e0b435...@corpmx14.corp.emc.com) about 'AC shut-down' on
Fri, 23 May 2003:
I wonder if anybody can substantiate or debunk a rumor that in New York
City, and maybe in New York State, there is a new requirement to
I read in !emc-pstc that Rich Nute ri...@sdd.hp.com wrote (in
200305231749.kaa15...@epgc264.sdd.hp.com) about 'Safety testing after
equipment repair' on Fri, 23 May 2003:
I stand by my statements.
You added a lot more information. In the light of that, I agree that
your results are likely to be
Hi John:
There is a justification for a high-current test **where it won't cause
any new damage**. The justification is that it will find bad joints in
the PEC path, and stranded PEC and bond wires that have only one or two
strands still intact.
The high-current test will NOT
All -
As a matter of curiosity, are there any records of drop-out
rates (for equipment that was required to be removed from
service)? Short of that, any anecdotes? Are the pass/fail
criteria identical to those during type testing?
Richard -
You say, former piece of UK legislation. As in,
I wonder if anybody can substantiate or debunk a rumor that in New York City,
and maybe in New York State, there is a new requirement to shut off air
conditioning systems in buildings in case of emergency, a post 9/11 measure.
It is an important issue: Since the computer systems can continue to
I agree with Alice on the arrangement of Hi-Pot for new products, but I
think the question was returned products for repair, correct. I read John W's
note with interest, but I also remember a note from Rich Nute about a test he
ran that pretty much pointed out that a simple continuity test
Hi John:
I don't think you can draw universal conclusions from just one
experiment. In addition, the rate of increase of voltage is limited in
the test procedures. In your experiment, there was only one increase of
voltage, whereas in repeated testing, there are many. At best, we
Ah Yes, emperical data; the essence of good engineering. Thank you Mr. Nute.
I have performed similiar long-term tests (I hope my employer does not see
this) on our iso xfmrs and component SMPS. I have recorded only (1) failure;
root cause was a (latent) manufacturing defect: pressure indentation
I read in !emc-pstc that Brian Epstein brian.epst...@veeco.com wrote
(in 41c71af75675d54bb97c2fadcae7f994260...@exchange.di.com) about
'harmonics testing' on Fri, 23 May 2003:
That raises and interesting question. The components are not in a rack or
case, they are tabletop mounted. I would
Steve,
That raises and interesting question. The components are not in a rack or
case, they are tabletop mounted. I would think that systems on a tabletop
would be less in need of being tested as a whole, but para 6.3 doesn't say
that.
Best regards,
Brian Epstein
Sr Regulatory Compliance
Rich,
I have only one question
concering the deterioration,
initally tested at higher cuurent for ground bond,
then over months?(time)..a lower current would be used..
is there a chart for what current might be used?
based on:
age
humidity of installation
current running thru it continously.
I'd
Rich,
is the below information true
for both the AC and DC hipot methods?
Some companies have contractors,subcontractors,
incoming and final hipot...
so it does and can occur at least 4 times,
before its shipped to a customer.
Richard,
From: Rich Nute [mailto:ri...@sdd.hp.com]
Sent: Thursday,
I read in !emc-pstc that ssel...@yorkemc.co.uk wrote (in E19J8TQ-
000cv7...@anchor-post-31.mail.demon.net) about 'harmonics testing' on
Fri, 23 May 2003:
Brian/John
I notice that EN61000-3-2(2000) para 6.3 says Where individual
self contained items are installed in a rack or case, they are
Brian/John
I notice that EN61000-3-2(2000) para 6.3 says Where individual
self contained items are installed in a rack or case, they are
regarded as being individually connected to the mains supply. The
rack or case need not be tested as a whole. So, is it a rackfull of
systems, or a system
I read in !emc-pstc that richhug...@aol.com wrote (in 014C7BA9.2FB45A16
.0ba45...@aol.com) about 'Safety testing after equipment repair' on
Thu, 22 May 2003:
For earth bond test we suggested that only a low
current would normally be required because the equipment would have been
type tested at a
I read in !emc-pstc that Rich Nute ri...@sdd.hp.com wrote (in
200305230123.saa09...@epgc264.sdd.hp.com) about 'Safety testing after
equipment repair' on Thu, 22 May 2003:
Some years ago, I undertook a test to determine when
an insulation would fail if subjected to a continuous
hi-pot voltage. I
I read in !emc-pstc that Brian Epstein brian.epst...@veeco.com wrote
(in 41c71af75675d54bb97c2fadcae7f994260...@exchange.di.com) about
'harmonics testing' on Thu, 22 May 2003:
We make a product that has several components that plug into the power mains
including a computer, two monitors, and two
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