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What were these 48 VAC tubular bulbs really used for?

Started by Babybearjs, January 15, 2018, 12:06:02 AM

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Babybearjs

found these through a collector down in Santa Rosa, CA. the price was right, but 48 Volts? what were these for? colored T6 lamps, like those used in exit signs.... Hmmmmmmmmmmm.... anyway, does anyone know what these were used for?
John

AE_Collector

Don't know exactly but of course Telephone CO's were all 48 VDC. Some sort of alarm or indicator panels I guess.

Terry

Babybearjs

I was intrigued with these.... I can wire 3 of these in series and make some light... first time I've ever seen a T6 bulb in a 48 Volt version.... wonders never cease...
John

kb3pxr

Central office alarm indicator lamps. There were different alarm conditions (and severity levels) and an indication was needed to aid in troubleshooting. Lamps would be installed at various places in the office to be seen from many points, especially in panel and step-by-step offices. ESS alarms were usually handled at a central point, I'm not 100% sure about crossbar.

AE_Collector

In our SxS offices, White was Perm (hung or held switch), Green was a minor and Red was a major. But our lamps were the more conventional small sized bulb like appliance bulbs.

Terry

kb3pxr

The truth is, unless we hear from someone who worked at the office these lamps came out of, we won't know the actual truth. Practices for alarms varied between companies and possibly even offices. Unless we figure out the actual use from either someone who worked there or from documentation we can really only speculate. Alarm lights (specifically Main Aisle Pilots) make the most sense to me though.

Babybearjs

I was under the impression that CO's always used 11S14 lamps for their alarm indicators, but it looks like they had a wide range of lamps that were used. the T6 lamps are different... its like using the old C6 Christmas lights, rated at 14.4 Volts, they were wired in series.... when I do a search for 48 Volt bulbs, not a lot comes back.... mostly 48PSB. definitely a speciality bulb... (that's now in LED)
John

kb3pxr

The 11S14 does match the photos I saw. I searched for 48 volt lamps and mainly found 6S6 in clear and 100A19 in frosted. Neither type surprises me (666 is available in many voltages between 6 and 230, and 100A19 is available in many voltages between 12 and 300).

Babybearjs

no, what I posted was 15T6 bulbs. I was using that as a reference to the regular type bulbs I've seen used before. the ones I have are probably the same ones that were on switchboards and other equipment as regular lighting. (soffit lighting) the bulbs I got today are carbon filament bulbs, so I figure they must be pretty old. I have yet to test them....
John