[AMPS] Series Parallel Electrolytics & Current

[Rich Measures]

>
>
>I need to build a filter bank for 8 kv @ 3 AMPS, WHAT are the
>considerations  for series and and parralel operation of two
>electrolytic banks to obtain 40 to 50 uf at 10kv? 

 105º deg C rated electrolytic capacitors last much longer than 85º C rated electrolytics.  -  -   I would use 2x 24 Panasonic [Matsushita] 470uF, 450v, 105º C rated units in series parallel. This would deliver about 40uF @10.8kWV.  I would use one 100k ohm, 3w equalizer resistor across each pair of paralleled 470uF units.  It is my opinion that for SSB operation, less C would work ok.  Also, I would mount the individual electrolytics on a 
7mm or more-thick acrylic sheet with silicone rubber adhesive to reduce case stress.   (Digikey currently sells these caps. at c. $12.20 each in >10 unit quantities.)  

> Oil capacitors are
>hard or too expensive to find. The Current rating of most
>electrolytics are around 1 amp, how would they operate at this current?

 At 3A on RTTY,   Hot.  The solution is to use paralleled units to divide the ripple current burden.  It's not a bad idea for electrolytics to be mounted with air gaps and to use a bit of forced air cooling.    
>
>
-  later, Igor


Rich. Measures.  Web site:  www.vcnet.com/measures


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