Re: Capacitive Ballasting

["Tesla list" <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>

Jim,

When used on the LV side, capacitive ballasting may not work nearly as
well as inductive ballasting. It also gives you a leading power factor
(current leads voltage) which may cause problems elsewhere in your
home's power distribution system. 

Where capacitive current limiting really seems to pay off is in the HV
side in DC coils that use the voltage doubling circuit originated by
Marco and discussed by Greg in a recent posting (See the "How to tame a
Wild MOT" thread).  

Best regards,

-- Bert --
-- 
Bert Hickman
Stoneridge Engineering
Email:    bert.hickman-at-aquila-dot-net
Web Site: http://www.teslamania-dot-com

Tesla list wrote:
> 
> 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