PSNet,
Here is a reference to an article describing an improved isolation
transformer design. It may be of interest to some here.
It can be found in the IEEE Transactions on EMC, Vol 443, No 3, Aug 01.
Title & Author: 'Characteristics of a Special-Isolation Transformer
Capable
of Protecting From High-Voltage Surges and Its Performance' by Akihiko
Yagasaki.
Abstract—Rapidly expanding computer-control systems and information
networks must be protected from high voltage surges and made immune from
noise. The usual method employed for this purpose is isolation transformers.
Conventional electrostatic-shielded transformers, however, are insufficient
for a number of reasons. The first is that many fine and complicated local
resonant circuits are created by the inhomogeneously distributed circuit
parameters inside the coil. The second is that common-mode surge noises
traveling on both the active conductor of the line through some common-mode
component change into normal-mode noise because of the unbalance between
their respective impedance values to ground. The third is the problem that
component changed into normal mode, propagate due to the electromagnetic
inductance from the primary to the secondary coil. In order to remedy this
set of problems, we must eliminate the high-frequency magnetic flux linking
the primary coil to the secondary coil through the air. In this paper, we
propose a design for a transformer that does not propagate high-frequency
components, even noise in a normal mode. We demonstrate dramatic noise
reduction in our experiments with the new design. We thus validate the
utility of coil arrangement for the purpose of noise reduction.
Index Terms—Conducting surge, isolation, isolation element, isolation
transformer, unbalanced parallel line.
Please find your own copy of this article. I am not a library and do
not
provide library services - I especially do not provide copies.
br, Pete
Peter E Perkins, PE
Principal Product Safety Consultant
Tigard, ORe 97281-3427
503/452-1201 fone/fax
[email protected]
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