These fluorescent lights

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pinkteddyx64
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These fluorescent lights

Postby pinkteddyx64 » 05 Jan 2018, 23:49

@spotify95 @Kyx

During my shift at work tonight, I noticed some of the flourscent lighting had a fault with it where it was doing a pinkish orange glow instead of the white light, a bit like the fault I've sometimes seen with LPS lights.

What is your diagnosis, spotify95?
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spotify95
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Re: These fluorescent lights

Postby spotify95 » 06 Jan 2018, 11:55

pinkteddyx64 wrote:@spotify95 @Kyx

During my shift at work tonight, I noticed some of the flourscent lighting had a fault with it where it was doing a pinkish orange glow instead of the white light, a bit like the fault I've sometimes seen with LPS lights.

What is your diagnosis, spotify95?


That will be due to loss of mercury in the tube itself.

When the tube runs out of mercury, the following failure mode occurs (courtesy of Wikipedia): "loss of mercury initially causes an extended run-up time to full light output, and finally causes the lamp to glow a dim pink when the mercury runs out and the argon base gas takes over as the primary discharge"

All of the end of life characteristics of fluoro lights (including CFL's) can be found here: https://en.wikipedia.org/wiki/Fluoresce ... nd_of_life

Failure modes include:

1. Emission mix - when the ends of the tube run out of emission mix and therefore cannot start the tube (this typically happens on tubes/CFLs switched on for less than 3 hours per cycle). Note that some ballasts can still start the lamp, allowing cold cathode operation (see point 5).
2. Ballast/electronics failures - more common in CFL's or lamps with integrated ballasts (with most fluoro tubes, you can switch out the ballast and replace it with a new one)
3. Phosphor inefficiencies - lamps left on for long periods of time, not failing under (1) or (2) will eventually fail under this mode. The lamp will still work but will be dim and inefficient (especially compared to a new lamp). This often happens around the 20,000-25,000+ hour lifespan area.
4. Loss of mercury - this will take over from (3) in some lamps that are left on continuously. Lack of mercury results in an extended warm up time to full light output. Lamp glows pink when mercury completely depletes, and argon takes over as the discharge gas.
5. Burned out filaments - the filaments at the end of the tubes can sometimes burn out, causing the tube to not light. In older lamps with magnetic ballasts, the lamp can flicker. This mode of failure rarely happens, unless the emission mix runs out (see 1) and cold cathode operation occurs. (Most fluoro ballasts will recognize this and shut the tube down before cold cathode operation can occur, see point 1.)

The Wikipedia article has some photos of tubes that have failed under one or more of the above, illustrating what to look for.

edit: I've also noticed some lamps in your screenshot with ends that are glowing orange. This is due to a weak or dead starter - though lamps left in this state for too long will destroy the lamps as well. They need new lamps and starter motors.



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