Date: Thu, 12 Sep 2013 18:55:57 -0400 (EDT)
From: Louis Parascondola <gudguyham@aol.com>
To: gudguyham@aol.com, ka4inm@gmail.com, amps@contesting.com
Subject: Re: [Amps] Clipperton-L question
I meant to qualify my statement that using an inferior switch for the job is a
bad idea as we can now see. I've changed switches in Clippertons that were
arcing a few times before they broke down bad enough to blow fuses. Swan and
Dentron in the 2000L used 12v relays to switch secondary HV and eventually the
contacts pit badly. Just about the only company that did a similar switching
arraignment that did it with proper equipment was Henry amps.
## The henry radio 8 k ulta and also 3 k ultra both used a spdt vac relay.
Problem is they are not latching types. They have to be wired so the
default, with no coil current, is LOW V position. Another issue when
using vac relays is you can only toggle between two taps. Now with more vac
relays, no big deal. A single wafer model 85 or 88-90-92 switch wont break
down, succumb to corona or any other fubar.
You can also get corona shields for any of the switchs..provided they are
single rotors. RF switchs usually use multiple pole rotors.... IE..shorting
switch.
## In actual usage, I havent see corona effects..sans corona shields, on any
85-88-90-92 switch..whether RF or B+ across the contacts.
## Either way... depending on the amount of C used in the B+ supply, you
will still get a big sec surge when switching from a low tap to a higher tap.
Bad enough switching from a 4800 tap to a 5200 tap...
and even worse when toggling from a 2300 tap to a 5200 tap. No big deal...
just shut off the 240AC, switch taps, turn it back on..and let the step start
do its thing.
## sure, you can also change primary taps...provided you have an appropriate
sized primary tap switch. I bought some surplus ohmite, double wafer, 100A
per wafer, tap switchs..and paralleled the wafers.
They actually still make em.... in 1-2-3 wafer configs. My 240 is all over
the map, varying from night to night..and also during the same night. Seen it
as high as 247.2 and low as 233. No big deal, as I have primary taps
at 198-208-218-230-240-250.
later... Jim VE7RF
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