Re: Current limiting

I had an interesting day Sunday at the the Gaithersburg, MD hamfest.  I 
didn't buy all that much at the hamfest, but I did meet and talk with 
Richard Hull and a few other members from the Tesla Coil Builders of 
Richmond.  Richard is a very nice person, and I got some good ideas 
from him in the half hour I was talking with him.

When I told him about my current limiting woes, he suggested a 
simple, inexpensive design for a current limiting choke.  Take a PVC 
tube and fill it with iron welding rods (use the powder coated rods to 
insulate the rods from one another and cut down on eddy current 
losses).  After that, all you have to do is wind the tubing with 10 gauge 
magnet wire (or whatever gauge you need to handle the current) and 
bring a tap out at the end of each winding to make it adjustable.  You 
can wind as many layers as you want for any amount of current 
limiting.  My only problem is finding the 10 gauge magnet wire at a 
reasonable price in the quantity that I need.  The local company that 
carries it only sells it in 80 lb spools (grunt)!  It's a good price, but 
about 10 times as much wire as I want!  Oh well, the search continues.

Steven Roys (sroys-at-radiology.ab.umd.edu)