Re: Fluorescent ballast life

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

Themysterious K9AUB at aol_com said:

> All - ALL - electronic devices, be they fluorescent
> ballasts, televisions, 
> radios, computers, light bulbs, anything, are affected by
> heat and voltage.  
> You simply cannnot predict the life of any of them,

Well yes and know.  The components, if used properly,
usually have average lifespans, safe operating areas, etc,
MTBFs and other ratings that can give a manufacturer an
idea about how long its devices might last.  That, testing,
and experience allow for some good estiamtes of expected
life.  If a ballast designer has no idea whether the
ballast will last longer than a year when used in a
reasonably normal way, then he ought to to quit the biz.

> but
> you can influence 
> their longevity.  For every volt over the rated voltage
> (usually 117 volts), 
> you can expect to cut about 10% off the life of the
> device.  

Yes, and this can be worse than 10% as the temps get higher
or the current is too high.


> Heat is under 
> your control.

This was truer for me when I lived in Santa Bararba, where
the temp was stable and enjoyable almost everyday of the
year.  Out on the  east coast, I it's much hotter in
summer.  There are limits to what I can do to hold down
room temps.  And that limits what I can do about the light
temps.

>  A ballast placed in open air with even a
> small amount of cool 
> air blowing over its service will last 4 or 5 times
> longer than a device 
> placed inside an enclosed case where heat is trapped. 

Yes, depending on room temps and how well the lamp sinks
the ballast heat.

> Voltage spikes are 
> another story; a lightning strike a few blocks away can
> destroy electronic 
> devices unless they are protected by surge protectors. 

Lighting strikes even farther away can be a problem.  It
lightning directly strikes your wires -- you probably will
suffer an awful lot of damage ["and *this* melted blob used
to be the stereo and that one use to be the surge
protector"]  Those are rare.  More often, the power lines
outside your house get a jolt from the eletromagnetic pulse
in the air that occurs from a flash of lightning.  The
power company (good ones anyway) have protection equipment
that snubs these jolts.  Voltage fluctuations occur as the
the the power is momentarily switched -- and switching
transients are sent through the wires too.  Good surge
protectors can absorb several of those before they fail --
how many depends on the surge protector design and the
amount of power involved.

> Look for surge 
> protected outlet bars in the computer department of
> stores.  Naturally, you 
> don't want to operate anything electronic near high
> humidity; 

I tried this, but every time I moved my aqaurium, the light
came with it ;-)

> avoid splashing 
> water on your ballast.  

Totally avoid it?  Don't let it happen at all.  You don't
want to keep tripping that GFCI you have everything plugged
into.

> If you address each of these
> issues and take care of 
> them, you can expect maximum life from your ballast.  If
> you don't, then 
> don't blame the engineer who designed it.  He did his
> job.

Well I was too quick with my comment ( quoted below).  Good
engineers put much of our world together and keep it
working.  Right now some of us are wondering if JBJ lamps
fail more than they should when used in perfectly normal
ways.  It also happens sometimes that a good engineer
specified the design one way, and marketing or finance or
management decides to go another way for other reasons. 
Some very big decisions have been made, ignoring the
engineers and rushing to adverse cosequences -- NASA comes
stereotypically to my mind in this regards, but
unfortunately the world is fraught with other examples. 
But if you can't get 5 or 10 years from a solid state
device used in the way it was reasonably expected to be
used, then the somebody is screwing the user and it isn't
necesarily a bad engineer.


Respectfully,
Scott H. 

> > Electronic ballasts should last for years and years,
> even
> > if cycled on/off several times a day or left running
> > continuously.  If you can't get 5-10 years as a typical
> > lifespan from a solid state device used as intended,
> then
> > the engineer that made the thing didn't do her or his
> > homework *or* the user is abusing the device  


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