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LISN ( line impedance stabilisation network for the mains )

E

Eeyore

Jan 1, 1970
0
I recall the schematic for one being published in one of the IEC
standards but not one I have at home.

Has anyone got a link to one ?

Graham
 
V

Vladimir Vassilevsky

Jan 1, 1970
0
Joerg said:
Considering the average age of this newsgroup artificial hip would be
more appropriate ;-)

A prostetic head is what really required.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
 
E

Eeyore

Jan 1, 1970
0
RFI-EMI-GUY said:
They left out the "artificial hand" part of the circuit :{

It's screened on the front panel I see if that's what you mean. My EMC mentor
had his own LISN that was distinctly home-made. It had NO markings.

So, who's going to ask me why I want one ? And will a Micrometals core be good
enough for the frequency range ? Must look up their materials. There's a nice
winder near here who stocks Micrometals. We used them for a passive post-SMPS
filter to get audio band noise really down to linear regulator levels.

Graham
 
E

Eeyore

Jan 1, 1970
0
Joerg said:
Considering the average age of this newsgroup artificial hip would be
more appropriate ;-)

I have funny arthritis. It was originally diagnosed as rheumatoid, but the
absence of progression led my Doctor to have more advanced tests done ( no cost
of course over here ). They reckon it's not rheumatoid after all. Still doesn't
explain why I get achy joints ( esps hips and knees ) especially when the
weather's cold.

Graham
 
E

Eeyore

Jan 1, 1970
0
Jim said:
Now be nice. Actually, when I had my hip replacement, they called me
the "kid", since I was the youngest recipient that day. Of course I
was also the only one who had polio as a child... leaves your joints
and spine looking as if you have severe arthritis :-(

Offhand, I can't remember the name of it but I did once work with a guy who had
severe movement problems due to a disease that causes the spinal cord to fuse
together. Not funny.

Graham
 
E

Eeyore

Jan 1, 1970
0
Vladimir said:
A prostetic head is what really required.

Did you you have Jim Thompson especially in mind ? ;~)

Graham
 
K

krw

Jan 1, 1970
0
I've met people who needed replacement at around 40. One of them a
pilot. Besides polio I guess some stuff is just genetic, nothing much
can be done about it in terms of prevention.

Rheumatoid arthritis is often the culprit. A cow-orker was in his
early '20s and could barely walk with a cane. I have some but it's
manageable without drugs. I thought I was going to start to have real
problems but it turned out a BP medication (Lisinopril) was attacking
my joints. The odd thing is my hips aren't bothered. Mostly knees,
feet, and hands. My shoulders were what tipped me off to the
Lisinopril connection.
 
P

Phil Allison

Jan 1, 1970
0
"Joerg"


** Boy, oh boy - that is one horribly dangerous piece of kit !!!

Anyone contemplating making one for their own user MUST READ the safety
warning on page 2.

The unit REQUIRES an independent ( ideally electrician installed)
PERMANENT safety ground connection to back up the one in the IEC inlet.

Without that safety earth, it is 100%, u-beaut technician killer.




..... Phil
 
L

legg

Jan 1, 1970
0
Many thanks Joerg.

Note that for measurements between 150KHz and 30MHz, only the
50uH/8uF/5R filter section is required. If you are anticipating
problems around 150KHz, the second section is advised in order to
reduce measurement complications due to the nearby self-resonance of
the simpler network.

The lower frequency section is normally intended only for measurements
extending down to 9KHz, which were not covered by CISPR. If you are
playing it safe and using air-cored inductors, the extra effort
required to produce it with appropriate materials is not
insignificant.

The use of a switch, or any 'power-on' fiddling with spectrum analyser
signal input routing, is inadvisable, but unmonitored lines should be
50ohm-terminated. The actual output coupling C value in the standard
is 0.25uF. Any in-house-built networks tend to raise warning bells and
eyebrows, now-adays. Calibration stickers and certificates of
compliance......yadda......yadda......yadda.

RL
 
E

Eeyore

Jan 1, 1970
0
legg said:
Note that for measurements between 150KHz and 30MHz, only the
50uH/8uF/5R filter section is required. If you are anticipating
problems around 150KHz, the second section is advised in order to
reduce measurement complications due to the nearby self-resonance of
the simpler network.

I was wondering about that since I've seen the simpler examples.

The lower frequency section is normally intended only for measurements
extending down to 9KHz, which were not covered by CISPR. If you are
playing it safe and using air-cored inductors, the extra effort
required to produce it with appropriate materials is not
insignificant.

Ah, but I am interested in lower frequency disturbances too. Thanks for the
advice.

The use of a switch, or any 'power-on' fiddling with spectrum analyser
signal input routing, is inadvisable, but unmonitored lines should be
50ohm-terminated. The actual output coupling C value in the standard
is 0.25uF. Any in-house-built networks tend to raise warning bells and
eyebrows, now-adays. Calibration stickers and certificates of
compliance......yadda......yadda......yadda.

This isn't intended for compliance, maybe pre-compliance but specifically for
'mains quality' testing related to susceptibility of audio gear.

I'm also interested in a simple but effective pulse generator to put noise on
the mains intentionally in a calibrated manner..

Graham
 
E

Eeyore

Jan 1, 1970
0
RFI-EMI-GUY said:
The artificial hand parts are missing from the schematic. I think it
is an RC circuit.

Ah. I don't recall using one. What's their purpose ?

Graham
 
E

Eeyore

Jan 1, 1970
0
Joerg said:
Well, pretty much all the ones I worked with (and it's been a lot) are
constructed like that. This kind of gear is meant to be used by
professionals who are familiar with conducted EMI measurements. In a
properly done EMI measurement setup you'll find large cables going to a
big fat rail. In my case that rail alone is 6mm thick, polished copper
and has 8mm DIN threads in there so you can torque things down real good.

There are many other things that just have to be engrained in lab
procedure. For example, quote "When power is to be disconnected, remove
the bnc connection to the measurement instrument first." Forget that
just once and ... bzzzt ... phut ... analyzer is toastissimo.

And indeed the tests are supposed to be done with the equipment bonded to a
nice big earth plane.

Graham
 
L

legg

Jan 1, 1970
0
Just a warning here: Make yourself a big warning plate to never, never
turn the connected unit off without _first_ unplugging the BNC cable.
And preferably there should be no power outages while connected. The
repair bill after a fried first mixer in a spectrum analyzer can be steep.

A 20dB input pad with internal transient suppression is always a good
idea when spectrum analyzers are involved in conducted line testing.

RL
 
E

Eeyore

Jan 1, 1970
0
Joerg said:
Yes, except that in certain markets you might have to watch "the grass
grow" down there. When it goes past the usual class B limits.

Thermal noise ?

Graham
 
P

Phil Allison

Jan 1, 1970
0
"Joerg = Jerk "

Well, pretty much all the ones I worked with (and it's been a lot) are
constructed like that.

** So fucking what ?

The danger is thoroughly hidden inside a nice looking box.

This kind of gear is meant to be used by professionals who are familiar
with conducted EMI measurements.


** So fucking what ?

The danger is hidden from ANYONE who comes near that nice looking but
lethal box.

In a properly done EMI measurement setup


** You are just so full of irrational shit.

There are many other things that just have to be engrained in lab
procedure.


** Go away - you ridiculous stupid old fart !!

Before you fucking electrocute someone.



....... Phil
 
J

john jardine

Jan 1, 1970
0
[...]
Just a warning here: Make yourself a big warning plate to never, never
turn the connected unit off without _first_ unplugging the BNC cable. And
preferably there should be no power outages while connected. The repair
bill after a fried first mixer in a spectrum analyzer can be steep.
[...]
-We- bought a HP141. -We- built a LISN. -We- did some tests. -Mr nobody-
then blew the spectrum analyser attenuator and first mixer.
-We- rung round for repair quotes. -We- blanched at the cost. -I- fixed it
( 2 hours and equiv a couple of dollars).
Nothing finer in life than showing off to the young uns :)
 
E

Eeyore

Jan 1, 1970
0
john said:
[...]
Just a warning here: Make yourself a big warning plate to never, never
turn the connected unit off without _first_ unplugging the BNC cable. And
preferably there should be no power outages while connected. The repair
bill after a fried first mixer in a spectrum analyzer can be steep.
[...]
-We- bought a HP141. -We- built a LISN. -We- did some tests. -Mr nobody-
then blew the spectrum analyser attenuator and first mixer.
-We- rung round for repair quotes. -We- blanched at the cost. -I- fixed it
( 2 hours and equiv a couple of dollars).
Nothing finer in life than showing off to the young uns :)

Showing your practical knowledge and ability to the 'young uns' ( and some of
the old uns too ) is IME one of the best ways to create a loyal and dedicated
task force.

At Neve I did work both in the metalwork shop ( they were busy - I had some
spare time and asked if I could help - and yes I learnt metalwork at what you'd
call 'high school' including using a 20 foot bed lathe ) and the test area that
really involved 'digging into things', that I was aware 'my guys' would always
go the extra mile for me.

Graham
 
E

Eeyore

Jan 1, 1970
0
Phil said:
"Joerg = Jerk "


** So fucking what ?

The danger is thoroughly hidden inside a nice looking box.

I've been involved with loads of LISN tests and never had any trouble. You don't
let dummies loose on that stuff.

Graham
 
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