Re: [APD] Re: Compact Question

["S. Hieber" <shieber at yahoo_com>]

Bill knows his stuff. 

However, I'm inclidned to not think it's cycling in
general. While starts take some life off of the filaments
and more frequent cycling tends to shorten bulb life, using
a wall switch also cycles bulbs. MOs uses of timers are
probably to run longer on/off cycles that applications
relying jsut on wall or lamp switches.

In-rush current shouldn't be a problem either, imo, if the
ballast doesn't want it, it won't be sucking it in. An
incandescent is more likely to draw a high in-rush current
-- in fact some digital timers (e.g. intermatics) specify
diff, lower maximum loads for incandescents than
fluorescents due to the higher in-rush that incadescents
cause compared to comparably watt-rated fluorescents.

Some mechanical timers don't have filtered relays but just
have a motor that turns a wheel with a cam or protjection 
that bumps a contact into or out of place. Some of these
can be rather sparky -- in fact the ones back in the 70s
sometimes started fires when the sparks burned the wire
insulation and the insulation then became slightly
conductive -- enough to allow for arcing and so it went.
The housings are beter now to contain the sparks but I'll
bet some of the cheaper ones are still sparky.

If the contacts are sparky, there will be insufficient
voltage to start the bulb, causing the bubl to try to start
several times for each single time that it's supposed to
start. That might be the reason.

Could some of the timers use FETs for the output couplers,
and if so, might these interact unfavorably with some
electronic ballasts? Perhaps the feeback on the power line 
from the ballast at lamp start and stop is destructive to
the FETs. That wouldn't surprise me -- fluorescents are
pretty dirty devices.

Of course, one of use to write the manufacturer and jsut
ask? ;-)


Scott H.
--- Bill Wichers <billw at waveform_net> wrote:

> 
> >I just picked up a few 15 watt compact bulbs for lamp
> use and noticed that
> >they said to not use them on timers. That doesn't make
> any sense to me. Can
> >anyone tell me why ?
> 
> Most likely this is for one of two reasons: Either the
> bulbs don't like 
> starts (which is likely), or they aren't rated for
> long-term cycles (like 
> having a timer run the light all night).
> 
> Most likely the bulbs have a limited number of starts
> (actually the ballast 
> is more likely to have limits than the bulb, but I'm
> assuming you have on 
> of the integrated bulb'n'ballast units). The ballast
> probably is only 
> expected to handle x number of starts, and the
> manufacturer assumes that a 
> light on a timer will have more starts than one that is
> only lit when 
> needed. Although this still seems strange, I think it is
> the most likely 
> explanation.
> 
> The only other possibility I can think of is that the
> bulb/ballast unit has 
> its own power switch and doesn't like it when it is
> turned on/off by power 
> cycling as would be the case with a timer. It's possible
> the inrush current 
> when the ballast is first powered isn't handled well
> internally. This would 
> be a bad design though, but the kind of thing that would
> save money for the 
> manufacturer of a cheap unit. A timer is just a gizmo
> that turns a switch 
> on and off with a clock (essentially), and electrically
> isn't any different 
> than flipping a switch on and off periodically. As a
> result, the reason for 
> the light not wanting to be on a timer should be related
> to what the 
> manufacturer thinks will be different about a timer
> operating the light 
> rather than a person.
> 
> What kind of light assembly did you just pick up?
> 
>       -Bill
> 
> 
> *****************************
> Waveform Technology
> UNIX Systems Administrator
> 
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=====
Still some time to get the $59 registration rate -- it must increase as of October 28th to $79.

But the convention hotel rate is sold out!

A "leisure rate" of $119 per night might still be available at the hotel -- requires Friday night (the 12th) stay. Contact the hotel  
hotel directly at (703)920-3230. The generic reservation line may not offer you the "leisure rate."

Alternative hotel info should be posted soon.

The Annual AGA Convention, 2004, November 12-14.
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