On Oct 30, 2006, at 1:43 PM, pentalab wrote:
--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@...>
wrote:
a friend and I had the same problem once with a qro rig and went
with two tall insulated standoffs with a singls strand of RG8
shield. Smaller wire would fuse at lower currents. gfz
## I have used the exact same deal... used one single strand from
the multi strands in the Belden 10 kv test prod wire. One day it
blew. [op error]... and blew right away [no load] when replaced.
### Stuck my dvm between chassis and top of each insulator [all
HV wiring removed at each end, no fuse wire]... and the output
insulator read a DEAD SHORT ! How can a 1.75" tall insulator
read a dead short? Got in with a dentist mirror.... and on the
back side.... it had vapour deposited top to bottom ! Scrubbed
it off... all was well. If that had been the INPUT insulator,,, I
could have easily smoked the 3 A diodes,
3A diodes will do 200a-pk. Not many HV transformers will. The original Plywood Box amplifier used 150a-pk, 2.5A avg diodes in a FWB and the diodes survived at least 4 flashovers to gnd without benefit of a HV fuse.
...
R L Measures, AG6K, 805.386.3734
r@..., , rlm@..., www.somis.org
