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Re: Fluorescent Lights: Troubleshooting and other questions

Subject: Re: Fluorescent Lights: Troubleshooting and other questions
From: Don Klipstein
Date: Sat, 10 Jun 2006 03:58:35 +0000 UTC
Newsgroups: sci.electronics.basics
In article <1149833782.998441.263680@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>, Uriah 
wrote:
>Someone told me that if you leave a burned out fluorescent bulbs in
>their fixture with power applied you eventually damage the fixture.
>Then if you put a bulb in it will burn it out in a second.

  Ballast damage is unlikely but I have known it to happen.  Damaged 
ballasts usually make themselves known very quickly - usually by not 
working at all.

  More likely trouble from keeping a burned out fluorescent lamp operating 
is if there is also a starter - and that can wear out the starter.

  Bad bulbs are hard on starters and bad starters are hard on bulbs.  But 
if you replace the bulb and only the ends glow due to a bad starter, the 
bulb suffers only minor to minimal damage if you pull either the bulb or 
the starter upon recognizing that this is happening.
  If the ends of the bulb glow *brightly* and the bulb does not start, it 
gets more urgent to pull at least one.  Otherwise the ballast can 
overheat.  Although UL testing supposedly means that the risk of a fire 
starting from this is negligible or "acceptably low", I know of one 
ballast that started a fire that way - in an elevator in an apartment 
building that I lived in before.

  If there are no starters and a replacement bulb does not start, check 
for:

1.  Fixture is properly grounded.  This sometimes affects starting by 
affecting the electric field distribution within a bulb that is trying to 
start.

2.  The bulb ("lamp") is of a type that the ballast is rated for.

3.  Corroded connections, loose wires, etc.

  After that, in my experience most likely the ballast died.  And in my 
experience, they die from at least mainly old age more than from 
attempting to run burned out bulbs.  They are designed to not die from 
burnouts occurring when it will be many hours or days before maintenance 
workers do anything.  Any ballast manufacturer designing a ballast likely 
to be used in commercial buildings I consider incompetent if the ballast 
is unable to survive working with a burned out bulb for months.

 - Don Klipstein (don@xxxxxxxxx)

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