Re: Edge Wound Primaries

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Mddeming@xxxxxxx 

In a message dated 12/8/05 9:27:08 P.M. Eastern Standard Time, 
tesla@xxxxxxxxxx writes:
Original poster: "Angelini, Frank J" <FrankJAngelini@xxxxxxxxx>



  I have several old magazine articles from the 1920's - 40's.  Many
of the TC's advertized for purchase had edge-wound  primaries. They
used thin copper or brass ribbon stock, approx 1/2 - 3/4 - inch
wide.  Why was this design used?  Is there an electrical
advantage?  I have also seen this method of coil winding used in ham
radio gear.  Is special machinery required to edge-wind a primary
coil or can this be done in a home workshop?

Thanks


Hi Frank,

    Ribbon stock was much easier to obtain than 1/4" copper tubing 
in the years prior to widespread residential air conditioning. Ham 
radio gear usually operated at 8 kV or less and this made for more 
compact coils since corona loss was not a major problem at these 
voltages. TCs operating at double or triple these voltages can have 
such problems, but for many people in those days, the blue glow on 
coils and caps had more aesthetic appeal than did peak efficiency. A 
ribbon coil has more effective capacitance than a tube coil of 
comparable dimensions. This may or may not be an asset. As one 
who  tried as a child to put the mainspring back in a watch, I will 
leave the fabrication problems of ribbon coils  to those who have 
done it to their satisfaction.

Matt D.