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Author Topic: Air Variable Capacitor voltage Ratings  (Read 35039 times)
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K9PNP
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« Reply #25 on: January 27, 2011, 02:10:49 PM »

Hi Guys:
Shane - KD6VXI.
Which edition of Bill Orr, W6SAI, handbook did you use?
73,
Chuck - AA5WG

It's also in the 1959 version.
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73,  Mitch

Since 1958. There still is nothing like tubes to keep your coffee warm in the shack.

Vulcan Theory of Troubleshooting:  Once you have eliminated the impossible, whatever remains, however improbable, must be the truth.
aa5wg
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« Reply #26 on: January 28, 2011, 11:27:59 PM »

Shane:
Thank you for the info. regarding W6SAI handbook.
73,
Chuck
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w1vtp
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« Reply #27 on: January 29, 2011, 01:44:50 PM »

Quote
The actual data looks a little "squiggley"  I did a trendline to make it into a "predictable" curve

Al

<snip>
Next overlay all the graphs and see which are conservative vs optimistic. Take the mean average and it probably realistic.

There is a mention of RF vs 60Hz voltage and also humidity, maybe buried somewhere on W8JI's site or a discussion on one of the amp forums.

Carl

That can be done. Maybe  I'll take a look at things after I finish my #$%^& weekly finances. ARGHHH

Yes, these graphs are to be done with all the above variables, humidity etc.  There's a lot of Kentucky windage involved.
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w1vtp
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« Reply #28 on: January 29, 2011, 02:30:24 PM »

Carl

I took my overlay data from three sources: W6SAI, Johnson, Cardwell, and ARRL.  I had to do some interpolating on some points. Actually they tracked pretty good.  I have included the spreadsheet this time so my data can be reviewed.  I'll include a snapshot for those who don't have Excel.  Actually, I think the numbers track pretty good. As before, the solid line is a "trend line" The actual data is the dotted blue line.

Added the overlay.

Al

* OVERLAY & VAR CAP BKDWN E VS SPACING.xls (40.5 KB - downloaded 220 times.)

* AVERAGE BREAKDOWN E VS SPACING.jpg (72.6 KB, 716x521 - viewed 516 times.)

* OVERLAY & AVERAGE BREAKDOWN E VS SPACING.jpg (37.8 KB, 715x523 - viewed 493 times.)
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W1RKW
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« Reply #29 on: January 29, 2011, 05:24:58 PM »

Lowe's sells a digital vernier caliper made by General that does fractiondown to 1/64, decimal inches out to 4 places and metric out to 2 places for $25 or $30 and it's not cheap looking either.   Works quite nice and feels good in the hand. And it seems fairly accurate too.

As measured on my Digital Volt meter, the cap is ~40uf (or 0.040nf, if you prefer) per section, with voltage spacing at/near 9/16" of an inch (better'n 10kV).

anyone interested in it, before it goes on e-pay?




I think you likely mean 40pF

or   0.04nF

 Grin
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Bob
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His fear was when I turned it on for the first time life on earth would come to a stand still.
w5omr
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« Reply #30 on: January 29, 2011, 06:26:56 PM »

All you guys have been awesome with your answers and thank you, Al, for the Data.

9/16" of an inch is pretty high-voltage spacing.  But, yes.. 0.040nf does equal 40pf.

Getting back to the actual capacitor, there's 3 plates on the rotor, per section, and 2 on the stator.
So, it's a split-stator 40pf capacitor, with somewhere in the neighborhood of ~15kV spacing.

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Patrick J. / KD5OEI
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« Reply #31 on: January 29, 2011, 08:10:38 PM »

As measured on my Digital Volt meter, the cap is ~40uf (or 0.040nf, if you prefer) per section, with voltage spacing at/near 9/16" of an inch (better'n 10kV).

anyone interested in it, before it goes on e-pay?




Might be good for a 3CX3000 6M amp. What LWH dimensions overall and shaft size does it have?
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w5omr
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« Reply #32 on: January 29, 2011, 09:03:30 PM »

Might be good for a 3CX3000 6M amp. What LWH dimensions overall and shaft size does it have?
The Frame is 10" long, 6 3/4" wide and around 4 1/2" tall.



* IMAG0184.jpg (1579.72 KB, 3264x1952 - viewed 549 times.)
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KM1H
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« Reply #33 on: January 30, 2011, 12:16:39 PM »

Maybe good for a 20-10M amp with the sections in parallel, will also need a low output C tube for 10M.

Or use it for a 20-10M ATU for that 3CX3000 or YC-156 amp.

Carl

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