[rescue] Big Caps

[Dave McGuire]

On July 4, Scott Newell wrote:
> >> The theatre at Rice uses banks upon banks of capacitors at about that
> >> rating in dimmer modules for the three-phase lighting system.
> >
> >Must either be way old, or way new.
> 
> I don't believe it.  All the farad sized caps I've ever seen are polarized
> and very low voltage--think 2-5 volts, not 480 VAC.  Why would you need the
> much energy storage in a light dimmer?  Even power factory correction banks
> for large factories with lots of rotating iron don't need farad sized caps.

  Yeah this is pretty ridicluous.  All the big high-power dimmers I've
seen have been TRIAC-based.  Big heatsinks, big fans, big TRIACs, but
no big caps.

  Even if they were the old resistor-bank-style dimmers...THEY didn't
even use big caps.

       -Dave

-- 
Dave McGuire                  "Needing a calculator indicates that
St. Petersburg, FL              your .emacs file is incomplete." -Joshua Boyd