Hi Brian:
What I've always wondered about, at least for class 1 construction, is just
what is really being tested by the pri/sec hi-pot, when the customer chooses
to ground the power supply's return.
(These comments presume the secondary is SELV.)
When you use a ground for safety
-Original Message-
From: Gert Gremmen [mailto:g.grem...@cetest.nl]
Sent: Thursday, August 22, 2002 1:06 PM
To: Bill Morse; 'Cortland Richmond'; ieee pstc list
Subject: RE: Emissions quick test
The technique of temperature variation is that
sensible, that heating up the *enclosure* of
a
I read in !emc-pstc that Brian O'Connell boconn...@t-yuden.com wrote
(in f7e9180f6f7f5840858d3db815e4f7ad1f2...@cms21.t-yuden.com) about
'electric strength test' on Thu, 22 Aug 2002:
Also,as some of our output-to-chassis Y caps are just 100V decouple caps,
Y-caps are specifically for connection
I read in !emc-pstc that Tyra, John john_t...@bose.com wrote (in
418fbd441c22d5118d860003470d43160543e...@cupid.bose.com) about
'electric strength test' on Thu, 22 Aug 2002:
If you plan on selling in
this region you should check all of the National deviations and maybe
contact DEMKO (part of UL
I read in !emc-pstc that Peter Merguerian pmerguer...@itl.co.il wrote
(in 2D1037012914D4118DB8204C4F4F50203DD9CC@ITLLTD01) about 'electric
strength test' on Thu, 22 Aug 2002:
You may come across some distributors in Norway asking for DI or RI
between PRI-EARTH, even for Class 1 power supplies.
I read in !emc-pstc that Rich Nute ri...@sdd.hp.com wrote (in
200208221745.kaa19...@epgc264.sdd.hp.com) about 'electric strength
test' on Thu, 22 Aug 2002:
Y-caps have enough margin to easily withstand
the 4300 V dc without damage.
Without immediate failure, no doubt. But such a huge
I just might have to try it and add it to the repertoire of troubleshooting
techniques.
-Original Message-
From: Gert Gremmen [mailto:g.grem...@cetest.nl]
Sent: Thursday, August 22, 2002 1:06 PM
To: Bill Morse; 'Cortland Richmond'; ieee pstc list
Subject:RE: Emissions
The technique of temperature variation is that
sensible, that heating up the *enclosure* of
a small box by hand !!! will be easily audible , if
the beat is down to only a 100 hz.
Just tapping on the pcb will also be audible, not
to let alone the effect of a freezing spray !
But you definitely
Brian -
From what I can glean from your message, the equipment is
Class 1, but the secondaries do not rely on earthing for
SELV reliability (hence, the Reinforced Insulation EST
value). However, there appears to be some functional
earthing of secondary circuits or there would be no problems
for
Some very useful replies from all.
What I've always wondered about, at least for class 1 construction, is just
what is really being tested by the pri/sec hi-pot, when the customer chooses
to ground the power supply's return.
Also,as some of our output-to-chassis Y caps are just 100V decouple
I agree with Peter, per the standard, and most IEC product standards, you
need two levels of protection from electric shock. In your case the y-caps
provide one level (basic insulation) and the earth connection provides the
second. As long as your earth path, between primary and secondary (I am
Brian,
Correction:
You may come across some distributors in Norway asking for DI or RI
between PRI-EARTH, even for Class 1 power supplies.
-Original Message-
From: Peter Merguerian
To: 'Brian O'Connell'; emc-p...@majordomo.ieee.org
Sent: 8/22/02 7:09 PM
Subject: RE: electric strength
I was going to make most of Ing. Gremmen's points but he beat me to the
punch. The most important point is that the injection, whether CI or RI IS
common mode, thus a common mode choke may be used with no resulting signal
degradation. Mr. Woodgate's comment about 10 Volts at 150 kHz is very
Hi Brian:
I am attempting to comply with both the letter and spirit of 60950:2000, cl
5.2. Note that 5.2.2 allows for separate testing, according the type of
insulation required. When testing a (class 1) power supply, the withstand
level for primary to chassis is Basic; and for
Brian,
Your interpretation of the standard and application of the test between
pri-sec is acceptable. You need to speak to a higher level person in the
agency who is an expert!
Please be advised that some countries do not have a reliable earthing
system. Many end-product manufacturers design
Yep, they're many ways of doing it. Heating the crystals and watching the
frequency of interest for variation, disabling the clocks one at a time, come to
mind.
They all have their uses and limitations.
-Original Message-
From: Cortland Richmond [mailto:72146@compuserve.com]
I read in !emc-pstc that Brian O'Connell boconn...@t-yuden.com wrote
(in f7e9180f6f7f5840858d3db815e4f7ad1f2...@cms21.t-yuden.com) about
'electric strength test' on Thu, 22 Aug 2002:
A (new) agency engineer says that inserting a piece of insulator defeats the
purpose of the test.
I don't see
Hi Joe
It's much more simple then that.
The EMC directive references harmonized Standards list.
The list of harmonized standards is listed
in the Official Journal = LAW.
The date of publication of the list is the date
that the standard may be used for the first time.
The list mentiones dates of
Hi Chris,
Let's start to state that you are probably over
estimating the effects of immunity test signals.
1/ The signals are common mode and present on the screen
initially and couples into the signal and powersupply
lines (DM) by the transfer impedance. 10 V of CDN couples signal
won't have
Good People of PSTC:
I am attempting to comply with both the letter and spirit of 60950:2000, cl
5.2. Note that 5.2.2 allows for separate testing, according the type of
insulation required. When testing a (class 1) power supply, the withstand
level for primary to chassis is Basic; and for
Thank you all for helping. I believe I know the right
approach now for devices that can straddle the fence.
It will be interesting if there is more clarification
about this before Oct 2002 like Mr. Woodgate
mentioned.
Neil, my scenario for the laptop needing E-Mark would
then only apply to the
Patrick writes ..
Fortunately for me this issue went away fast as
it came up and I was told I don't need to pursue
this any further for now.
I am afraid this realisation comes too late! The group has already
sent its responses. I don't see that you have much of a choice
now but to
I read in !emc-pstc that Chris Chileshe chris.chile...@ultronics.com
wrote (in 01c249c6.f7fe8500.chris.chile...@ultronics.com) about
'Designing for low power conducted and radiated immunity' on Thu, 22 Aug
2002:
1 - I need to let a bit stream through at 25kHz, but reject RF at 150kHz
Dear all,
On the evidence of the quality of responses I have seen on more difficult
queries, I think this should be fairly straightforward for all you RF engineers
out there.
My product is a small 3-wire pressure sensor which sends out a digital bit
stream encryption of the pressure measured.
All
I am looking for a needle flame test set up equal to the test set up in
GR-63. Can anyone point me to a supplier of this type of test gear?
Dan Anchondo
Associate Compliance Engineer
CIENA Corporation
10480 Ridgeview Court
Cupertino, CA. 95014
Main (408) 366-4700
Direct (408) 366-4942
Just a note about telling clocks apart... unless they're phase locked
(sometimes even then) a receiver with a BFO can let you distinguish from
among clocks only 100's of Hz apart. Sometimes it can let you tell which
of several clocks is slower to lock as well, as you can hear the varying
tone
Joe Martin wrote:
Credence Technologies manufactures a probe with a built in low noise
amplifier
Ohmygosh, yes. How could I have forgotten THEM! An untuned probe, with
output to a scope or analyzer, too. Neat tool.
I spent a fun half hour or so talking to their very bright son last year
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