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Re: HV & ballasts

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

> Rule of thumb: 10W per foot of tube.  So that's getting
> on to 1A per ballast.  But.  Most such are 'rapid start'
> single pit tubes, with internal resonant circuit to
> make the spike.  I have this Sneaky Suspicion this would
> make them Very Complicated (==unstable) to work with.
> (and, sometimes, even with two pin lamps, electrically,
> the tubes only use open tube and the rapid start
> ballast.)
> >(which are being replaced....)... We used to have a bunch at my
> >former work which were 160W (I can't recall if it was 2 tubes at
> >160 each (i.e. 320 W all told) or 2 80W tubes..).

Actually, they were 120W tubes (having just called the shop manager and

Also, I find (on one of the zillions of web sites that talk about how
wonderful brand X ballasts are)  that "rapid start" means that they apply
power to the filaments and HV to the tube simultaneously.

There is a capacitor on some ballasts, across the power line, to do PFC.
Easily distinguished, because the ballast will either say (in tiny print)
something like PF=0.75, or, in great big type "New Improved Power Factor


And, yes, a bunch in parallel...

Say you had 15 of them... I'd wire them up in a 1,2,4,8, kind of pattern,
giving you (in this case), 16 power steps (actually 17.. no ballast)