EOL Tubes On Thermal Starters?

Topics relating to lighting control gear, including magnetic & high frequency ballast and ancilliary devices such as starters, ignitors and switchgear.
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Tom
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EOL Tubes On Thermal Starters?

Postby Tom » Thu Feb 18, 2016 11:13 pm

Has anyone ever witnessed a tube failing on a thermal 4 pin ballast and starter switch. Upon switch-on, the starter closes and preheats the tube's cathode filaments. Upon opening, the magnetic field within the ballast collapses, causing a voltage pulse which strikes the tube. This is often repeated twice or more, causing the distinctive blinking at startup.">switchstart circuit? I'm just curious to whether the rectifying lamp would still pass enough current to keep the heater coil and contacts open, allowing the tube to shimmer away. Or would the rectifying tube cause the starter to cool down resulting in a slower end of life flashing cycle?
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Paul
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Re: EOL Tubes On Thermal Starters?

Postby Paul » Thu Mar 10, 2016 3:34 pm

I guess not Tom... looks like it must be an experiment for us to carry out!

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Zelandeth
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Re: EOL Tubes On Thermal Starters?

Postby Zelandeth » Fri Apr 01, 2016 10:38 pm

Pretty sure we had some 5' 80W tubes on thermal starters in my first primary school. The usual behaviour we saw there was for them to dim right down to just a faint argon pirple glow that would get progressively dimmer over a few days until then finally went right out. Then they would blink once every few minutes.

I don't know for certain they were thermal starter equipped mind you...one they were about twenty feet up in the hall, and two it was about 25 years ago! They were pretty ancient fittings even then though.

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Paul
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Re: EOL Tubes On Thermal Starters?

Postby Paul » Sat Apr 02, 2016 1:03 pm

Did the cathodes glow at the ends?


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