This is a good suggestion. I think there is a problem with too much series
inductance between the LISN and EUT power supply.
The EUT has two power supplies so I may be able to plug one into a non-LISN
source first, then plug the other into the LISN. Then I can try to remove the
non-LISN source to see if the EUT stays powered on.
Thanks to everyone for their ideas.
Regards,
Tim
In a message dated 8/31/2010 5:46:55 A.M. Pacific Daylight Time,
[email protected] writes:
Tim:
Again, I’m guessing at what your “problem” is, but following Ari’s
supposition, here’s another tip.
I have sometimes encountered devices that try to start by drawing a
heavy current surge, but then, either due to ohmic or inductive voltage drop
across the LISN, refuse to start. I simply connect a wire jumper from the LISN
source to load terminals, start the EUT, and then remove the jumper.
Sometimes, a “watchdog” circuit in the EUT will not allow starting if
the input voltage is too low, You might get around this just by setting the
power supply voltage to the EUT’s maximum input voltage, starting the EUT, and
then setting the voltage to nominal. OTOH, sometimes the maximum and minimum
watchdog set points are so close together that you wonder how the gadget ever
works in real life.
Ed Price
[email protected] <blocked::mailto:[email protected]> WB6WSN
NARTE Certified EMC Engineer
Electromagnetic Compatibility Lab
Cubic Defense Applications
San Diego, CA USA
858-505-2780
Military & Avionics EMC Is Our Specialty
From: [email protected] [mailto:[email protected]] On Behalf Of
Honkala, Ari (Espoo)
Sent: Monday, August 30, 2010 10:33 PM
To: [email protected]
Subject: RE: Alternative Conducted EMI method for CISPR 22
Hi,
If the problem is that EUT does not start due to series inductance, you
may try to use LISN in parallel, as a voltage probe. The principle is explained
in CISPR 16-2-1 Annex A.5
Ari Honkala
SGS Fimko Oy
________________________________
From: [email protected] [mailto:[email protected]] On Behalf Of
[email protected]
Sent: 31. elokuuta 2010 1:20
To: [email protected]
Subject: Alternative Conducted EMI method for CISPR 22
Hello Group,
Does anyone know if there is an alternative conducted EMI power line
measurement method for CISPR 22? I'm having trouble testing a DC powered unit
with a traditional CISPR 16 LISN. Someone mentioned that a current measurement
can be made on power lines using a current clamp instead.
I could not find anything about measuring power lines with a current
clamp. What limits would be used? The only reference to current clamp
measurements in CISPR 22 is for telecommunication ports.
I know ANSI C63.4 mentions you can make measurements using a current
clamp, however CISPR 22 does not. Any information would be helpful.
Thanks,
Tim Pierce
TAP Engineering, LLC.
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