Re: Capacitive Ballasting

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

Original poster: "Steve Greenfield by way of Terry Fritz <twftesla-at-qwest-dot-net>" <alienrelics-at-yahoo-dot-com>

I think you need the diodes in parallel with the caps
and the caps in series. Otherwise each cap just
charges up via the diode and then blocks any more
current from passing.

As to the merits of this, I couldn't say.

Steve Greenfield

--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Alfred Erpel by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <alfred-at-erpel-dot-com>
> 
> 
> Howdy all,
> 
>  I was wondering about the merits of capacitive
> ballasting a transformer
> with electrolytic photo capacitors since you can get
> them for free from
> disposable cameras and they have high enough
> capacitance in a small enough
> footprint to be practical.
> 
> ASCII art warning -- make sure you have on a fixed
> width font. I use Courier
> New.
> 
> 
> 
>                    electrolytic
>          diodes     capacitors
>    -------->|--------|+ -|-------------o  o-----
>   |     |                   |          o||o
>   |     |                   |          o||o
>   |      --|<--------|+ -|--           o||o
>   |                                    o||o
> |A C|                                  o||o Xformer
>   |                                    o||o
>   |      -->|--------|+ -|--           o||o
>   |     |                   |          o||o
>   |     |                   |          o||o
>    --------|<--------|+ -|-------------o  o------
>                    electrolytic
>          diodes     capacitors
> 
> 
> Would the above circuit have any problems? Is this a
> stress for a good
> electrolytic?
> X(c) = 1 / (2*pi*f*capacitance)
> At .000160 F and f=60 Hz, a typical photo
> electrolytic yields a reactance of
> 16.578 ohms. Putting 4 in series would yield 66.315
> ohms which would limit
> 115 volts to 1.734 amps. I know one thing to worry
> about would be that you
> aren't around resonance with the transformer's
> primary. How would each leg
> of the circuit "see" the capacitance? For instance,
> if the circuit above
> just had four 160 uF capacitors (one for each
> diode), for calculating
> reactance would you use 80 uF in the reactance
> equation or 320 uF? Would it
> even work?