I messed up here.
Adding two series sections cuts the capacitance in half, and paralleling them
increases it. Why I got turned around I don't know. Anyhow, jumping the screws
over adds capacitance so strike all else I said. Sorry about that, I've been
looking at evay too long today and it fried my brain, LOL! However, the voltage
rating can only be changed by increasing the air gap that I know of. You'd
still have to have one end of the cap to the tank coil, and the other to ground
for it to work. The rotor is connected to frame ground via a wiper on the
shaft. The stator is insulated from the rotor. I can't think of any other way.
Best,
Will
*********** REPLY SEPARATOR ***********
On 3/19/06 at 10:44 PM Will Matney wrote:
>Scott,
>
>The capacitors rotor has to go to ground, and the stator to the tank coil
>to work. Generally, the rotor is connected through frame ground via a
>wiper. The stator is insulated. There's no way of increasing the voltage
>unless the plates are spaced further apart. If you series the sections by
>using a jumper across the screws, you increase the capacitance, not cut it
>in half. You have to paralell them to do that and there's no way to do it.
>To get less capacitance, or cut it in half plus raise the voltage, remove
>half the plates at every other plate. That will increase the air gap and
>the voltage rating, plus cut the capacitance of the section in half. Those
>plates will come off as they're just pressed on.
>
>Best,
>
>Will
>
>
>*********** REPLY SEPARATOR ***********
>
>On 3/19/06 at 4:19 PM Scott Townley wrote:
>
>>I have a dual (split-stator) 20-100pF air cap, 0.040" gap (so ~1500V)
>>I need a single 15-50pF, 3000V for a tank tuning cap.
>>So is there any reason I can't simply series-connect the split stators
>and
>>float the rotor? Obviously the rotor must be isolated from the chassis
>>now, and I won't get 20/2=10pF min due to frame effects, but I only need
>>15...anything I'm missing?
>>TIA,
>>
>>
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>
>
>
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