Re: Capacitive Ballasting

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <HomerLea-at-aol-dot-com>

I have LOTS of the old oil filled paper capacitors. Would they work ok?
Jim Heagy


> Subj:  Re: Capacitive Ballasting
>  Date:    2/25/02 6:16:09 AM Pacific Standard Time
>  From:    tesla-at-pupman-dot-com (Tesla list)
>  To:  tesla-at-pupman-dot-com
>  
>  Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
> <bert.hickman-at-aquila-dot-net>
>  
>  Al,
>  
>  Even if the diodes and caps were polarized properly, the circuit will
>  not work because the diodes will only allow current to flow through the
>  capacitors in one direction. This charges them but does not allow them
>  to discharge. Once all the capacitors are charged, you'll get little
>  further current flow except for capacitor leakage current. 
>  
>  However, the way that the diodes and caps are polarized in your
>  schematic results in two of the caps being charged with reversed
>  polarity. This is guaranteed to be exciting with polarized electrolytic
>  caps, since reversing polarity "unanodizes" the capacitors' internal
>  dielectric layer, causing it to break down, and letting the smoke
>  (actually steam) out... :^)
>  
>  A capacitor must be able to freely exchange energy with the surrounding
>  circuit, meaning that current must be allowed to flow into, AND out of,
>  the cap. Adding a series diode (to protect the cap) also blocks current
>  flow in the discharge direction, preventing the cap from working as
>  desired.
>  
>  Best regards,
>  
>  -- Bert --
>  -- 
>  Bert Hickman
>  Stoneridge Engineering
>  Email:    bert.hickman-at-aquila-dot-net
>  Web Site: http://www.teslamania-dot-com