In message <FCA549BE3ECF9D4CB8CB8576837EA48920A1A4@ZEUS.cetest.local>,
dated Sat, 7 Sep 2013, "ce-test, qualified testing bv - Gert Gremmen"
<g.grem...@cetest.nl> writes:
Anyway, the primary circuit always need to be build for high surge
currents,
and one should always insert induction to limit surge currents.
As the impedance of the spark gap is low, only a small amount of
induction
will reduce the surge current substantially
Quite true, but the mains supply itself (unless it's from a very nearby
private MV/LV transformer, has inductance of the order of a millihenry
(0.3 ohms at 50 Hz), so there is not much point in adding only a few
microhenrys.
IEC TR60725 gives 'reference impedances' for various types of mains
supply. While these tend to be higher than the actual impedance at the
'point of common coupling', they are a guide to the impedance at a
typical wall-socket. This impedance limits the prospective short-circuit
current.
--
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
If dictionaries were correct, we would only need one, because they would all
give the same information.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
-
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