[Amps] issue with AL-1200 output -UPDATE NUMBER 2-

[Joe Subich, 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.

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 at telus.net> wrote:
>>
>> Date: Tue, 27 Jun 2017 10:06:30 -0700
>> From: Tom Osborne <w7why1 at gmail.com>
>> To: amps at 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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