On 6/28/2017 3:59 PM, MU 4CX250B wrote:
> Good answer. Only thing I'll add is that the results are altitude
> sensitive. A larger gap is required at higher altitude, but I'm not
> aware of any charts.
On the other hand, an air capacitor also arcs at a lower voltage at the
higher altitude. When properly set to protect the capacitor at sea
level, the gap will be the same at altitude since the break down will
change proportionally for both devices. If using a "pointed" gap one
could most likely set the gap the same as the plate to plate spacing
as the pointed gap will break down before the parallel plates or even
the "leading edge" of one rotary plate to the adjacent fixed plates.
73,
... Joe, W4TV
On 6/28/2017 3:59 PM, MU 4CX250B wrote:
Good answer. Only thing I'll add is that the results are altitude
sensitive. A larger gap is required at higher altitude, but I'm not
aware of any charts. I just use trial and error. Santa Fe is at 7000
feet elevation, and water boils here at about 195F.
73,
Jim
Sent from my iPhone
On Jun 28, 2017, at 1:05 PM, Jim Thomson <jim.thom@telus.net> wrote:
Date: Tue, 27 Jun 2017 10:06:30 -0700
From: Tom Osborne <w7why1@gmail.com>
To: amps@contesting.com
Subject: Re: [Amps] issue with AL-1200 output -UPDATE NUMBER 2-
##Then a mating, non adjustable, ground down, 2nd machine screw. Then
some locking nuts etc, so when adjusted, tweaked, to the desired gap, its
then locked down.
____________________________________________________________
<Hii Jim
Would this work in an antenna tuner to keep it from arcing and blowing out
the bandswitch? How do you know when this is adjusted right? 73
Tom W7WHY
## Assume .5” = 15 kv .25 inch = 9000 V. .125 inch = 4500 V .0625
= 2250 V.
.03125 = 1125 V
Thats how air variables are rated.. between smooth stator and rotor plates.
Extrapolate
for in between values.
## I used feeler gauges for fine tweaking..and or digital calipers. If u
have an adjustable hi pot
tester, u can slowly bring it up, till the hb spark gap arcs..once. But that
only works if the gap is
at least pre-set to less than what u are trying to protect. That’s if u are
testing the gap..while its
actually wired to the device u are trying to protect.
## what u might want to do is aprx the gap..then with tuner in ...normal
operation.... see if gap arcs
or not. If it does, open the gap a tiny bit, till no arc under normal
operation.
Jim VE7RF
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