Date: Wed, 05 Jun 2013 11:19:12 -0700
From: Bill Turner <dezrat1242@yahoo.com>
To: Amps <amps@contesting.com>
Subject: Re: [Amps] German amp using ARF1500
ORIGINAL MESSAGE: (may be snipped)
On Wed, 5 Jun 2013 20:08:41 +0300, Baruch wrote:
>
>I wish you luck
>look at what this German guy did
>I have used this device too ,had good results.
>BTW the cap needs to be bigger than 680uF
>regards
REPLY:
The cap on eBay is 6800, not 680 uF. I figure with 6800 and 120 Hz input the
ripple should be about 1.5% using the formula at
http://www.ehow.com/how_8386631_calculate-ripple-dc-power-supply.htm
If that's not enough, I'll add another cap.
Thanks for the other info. I have a friend who speaks German, I'll ask him
to translate. All encouraging so far.
73, Bill W6WRT
### Bill, if you require some BIG lytics, http://www.rjrelectronics.com/
has loads of em, surplus..and still new in box.
10,000 UF @ 450 vdc. Aprx 3 inch in diam x 9 inch tall. They come
with a half inch or 5/8 inch threaded stud
sticking out the bottom. That makes for EASY mounting to anything, Machine
screw terminals used for the plus + minus.
I think they use 1/4-20 or 1/4-28 machine screws instead of the usual 10-32.
## forget what I paid, something like $15 to $20. Think they were 16 or
20A CCS ripple current rating, and ESR is
extremely low, just a few milliohms each. I measured the ESR on lytics using
my B+K 875B digital lcr meter. It measures
AC resistance instead of the usual dc resistance....and does it down to 3 x
decimal places. Done at 1 khz.
## I bought 9 caseloads of em, and 6 caps per case. 24 used in series to
make one bank....for a 7700 vdc B+ supply.
I put another 24 caps in there to make a 2nd bank of caps. Then paralleled
the two banks of caps, to make a 832 uf filter.
Each bank is fed via a Buss HVU sand filled HV fuse.
24.6 k joules in total for this config. . Glitch R consists of 4 parallel
Type AS energy absorbing globars. 200 ohms each.
1.5 inch diam x 18 inch long. Each resistor rated for 225w ccs...or 900 w ccs
for the total assy.
Each resistor rated for 119 K joule..and 120 kv. 476 k joule in total.
## Glitch R assy preceded with a Buss sand filled HVU series HV fuse. And
yes, you can short the output, from B+ to B-
and all that happens is the HV blows open, no fuss, no muss. Vac contactor
used to conduct that experiment.
## A pair of 10 inch diam fans, one above the other is used to cool both the
4 x 18 inch tall globars and also the entire HV cab,
plate xfmr etc. An air filter used at back end of cabinet. Fans on front suck
the air out the front.
## parallel all 3 poles on a 3 pole contactor to make one big spst contactor
assy. 3 x such assy’s constructed. One assy placed
in each hot leg of the incoming 240 vac. 3rd assy used for the step start.
Step start R consists of 6 x parallel 20 ohm resistors,
300w metal finned type. The rest is pretty conventional. Surplus 3 pole
contactors with either 120 vac or 220 vac coils are
readily available with 135A to 300A contact ratings.
## the above hv supply is for educational purposes, and used for various HV
experiments. It could also be used for broadcast,
Mars, Embassy, medical and military applications. ( good, that oughta keep
KM1H happy).
Later... Jim VE7RF
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