In message <ce36590e.46a97%[email protected]>, dated Sun, 18
Aug 2013, Ken Javor <[email protected]> writes:
"There is the unique 200 mA test method in EN 55103-2:2009, fig. B.3b)
and B.4 which uses a "toroidal transformer" for injection beginning at
50 Hz."
Yes, 50 Hz to 10 kHz, not 150 kHz.
He then states:
"I do not like the method's uniqueness and the lack of an usual
calibration procedure."
Tough. Most EMC test methods are 'unique'.
And he goes on to say he wants a bulk cable injection technique similar
to MIL-STD-461 CS114. That's where the the thread was punted my way.
I believe the committee concerned could not find a satisfactory method
of that type.
It's not too hard to inject 200 mA into a dead short, but as stated in
the original post, there must be some way to bound the driving
potential as well. A BCI technique at low audio frequencies is
non-trivial if a potential of any magnitude must also be delivered.
I don't understand this point. There is no question of requiring an
unlimited voltage. An example is given in the text of a 100 V
audio-frequency supply, fed via a 4.5 kohm resistor to a transformer of
voltage ratio 9:1. In parallel with the primary winding is a series
network of a 6480 μH inductor and a 20.25 ohm resistor. The calibration
requirement is that a short-circuit across the primary winding carries a
current of, in this case, 22.22 mA, +0/-0.5 dB up to 10 kHz.
The *maximum* current injected is indeed 200 mA, but the actual current
depends on the impedance of the loop, of course. This is satisfactory,
because it applies also to any real-life common-mode current.
I would point out that EN 55103-2 has been in use since 1997, and the
requirement has not changed. The standard will in due course be
superseded by CISPR 35/EN55035, which you client may like even less.
--
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
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