Old RCD/GFI Units

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Original poster: "Ian McLean" <ianmm-at-optusnet-dot-com.au> 

Hi all,

Just thought I would pass on an interesting find to the list.  I had an old
faulty RCD Breaker (GFI unit for all those in the U.S.) lying around, so I
decided to pull it apart in the interest of finding out how these things are
constructed and how they work.  On doing so I found a very useful component.

There is a current transformer inside these units, at least the ABB unit I
have.  The core of this CT is a coil-wound laminated steel toroid with a
plastic casing.  If you pull off the existing windings, I have found this to
be an ideal core for winding your own current transformer.  Seeing as CT's
are quite expensive, and we all here are interesting in scavenging parts for
our coiling projects, I thought I would pass this on for anyone that might
be interested.  I have used mine to wind a CT for an AC ammeter for my
coil's AC control box and it works great :-)

Rgs
Ian.