[AMPS] Re: Winding QRO Toroids

[Roy Koeppe]

Hi Tom, you asked,

Roy,

"When you wrap the core with the double leayer of glass tape, do you use
dope or anyother
substance on the glass?  I am trying to figure this out.  I read an article
by Jerry Pittenger
that said to use "core dope" from Radio Shack before winding the wires.  I
would like to
know if this is necessary or just put the glass tape, Scotch #27??, on the
core and then wind away.
Perhaps you can help me with this."

No, I can't imagine any reason for using 'dope'. The only reason we used
dope in the old days was to maybe hold tiny-sized wire in place on our
forms. Typical modern "enameled" wire has an insulation rating of around
2000 volts. The glass tape has several KV more. If your core is 'floating'
above chassis ground, which is the normal case, then the only voltage from
winding to core is that of the circulating, resonant swing. The winding
should cover about 3/4 of the core area, leaving 1/4 gap between the ends.
Turns are counted ONLY where they pass through the HOLE. I presume you have
a good data sheet of calculating instructions.

The adhesive on the glass tape is high quality--it sticks forever. Solid
wire windings stay in place by themselves. Stranded and/or teflon insulated
wire likes to spring back, so it usually is held by tie wraps, etc. (Dope
wouldn't stick to teflon anyway!!).

73,   Roy   K6XK     Iowa Outback




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