13:36 Apr 19, 2010 

Andrew are you perfectly sure it shouldn't be "ringkerntransformator"?

You can find one here:
http://nl.wikipedia.org/wiki/Transformator

and another one here:

Toroidal transformers (or: toroidal core transformers) are built around a ring-shaped core, which, depending on operating frequency, is made from a long strip of silicon steel or permalloy wound into a coil, powdered iron, or ferrite.

http://en.wikipedia.org/wiki/Transformer

a current transformer is called a "stroomtransformator" in Dutch


Anyway, it would seem that a "ring current transformer" is a current transformer designed as a ring ....

have a look:

http://www.alibaba.com/product-gs/279461574/ring_current_tra...

It could be that "ringstroomtransformator" is either a "ringkerntransformator" (a) or a wrong translation of "ring current transformer": ringvormige stroomtransformator. (b)

if (a) then you could translate as: toroidal core transformer
if (b) then you could translate as: ring current transformer, ring type current transformer, toroidal current transformer

http://www.globalsources.com/manufacturers/Toroidal-Current-...