Author Topic: Bulb burning for 100 Yrs? (Read 15785 times)

rschuett · « **on:** June 15, 2001, 01:07:00 pm »

I was listening to NPR the other week and caught the tail end of a guest on the show. I was traveling in the back woods and could only hear every other word or so, but the gist of the conversation centered on a 4W bulb that supposedly has been burning for 100 years. I thought it was called the "Millenium Bulb" but I couldn't find it on the Net. It is visible to the public, I thought I heard that it is on top of a building somewhere out west, maybe a fire co.? Can anyone else out there shed some "light" on the subject? Thanks

Rick S

Tim · « **Reply #1 on:** June 15, 2001, 02:20:00 pm »

Hey Rick,

Read all about it here:
http://www.centennialbulb.org/index.htm

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-Tim
BulbCollector.com
DewCollector.com

Chris W. Millinship · « **Reply #2 on:** June 16, 2001, 02:35:00 pm »

Isn`t that wonderful! A living tribute to how things in days gone by were made to last. I`d heard about it too but never found the site until now- thanks Tim!

I have a similar looking Shelby carbon bulb from about the same era, only with a Thomson Houston base (that one is a Westinghouse isn`t it- I didn`t see any referance to that on the site though?)- it works too but it`s highly doubtful that it was burning all its life until I got it. Most likely spent maybe 90+ years in a cupboard or attic.

Was it just me or was their web cam not working?

Chris W. Millinship · « **Reply #3 on:** June 16, 2001, 02:45:00 pm »

I just looked again and it`s working, probably was just network troubles. Maybe I should try and link it here so we can all see...updated every 30 seconds apparently...let`s see if this works......

Tim · « **Reply #4 on:** June 17, 2001, 02:02:00 pm »

Did you hack into that bulb cam Chris?

Cool idea!

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-Tim
BulbCollector.com
DewCollector.com

Chris W. Millinship · « **Reply #5 on:** June 17, 2001, 02:27:00 pm »

Nope. I just looked at the webcam page`s source code to how it was done. It seems the web cam capture system is connected directly to their web server and just uploads a new jpeg image file every 30 seconds, with the same address- http://www.centennialbulb.org/images/bulbcam.jpg . It was then just a simple case to hotlink it here and presto- it works (I hope they don`t mind though, if they do, please tell me and I`ll remove it). And doesn`t it look good! I hope it keeps on shining for another 100 years!

Tim · « **Reply #6 on:** June 19, 2001, 04:53:00 pm »

Well since we're on the Shelby subject here's my bulb. It's a ruby red glassed bulb with the familiar mushroom shape and an intact label. I picked this bulb up a few years ago while coming back from an antique engine show in northern Michigan. I came upon a sign with a big arrow saying "BARN SALE TURN LEFT", so of course I did. I found an old rusted out tungar bulb charger in the barn along with the usual cool junk so I asked if the dealer if he had any old bulbs. He pulled out a large box of early bulbs but all were dug from the ground and were in poor condition. The junk guy then told me that he had a "special one" hidden away some place in the upper loft of the barn that once belonged to his father. After convincing him to find it for me he returned from the loft with this and asked if I had an interest:

Not trying to show too much enthusiasm, I told him I was interested and asked him for his price. $15 later I had a mint and working ruby Shelby! Now if I could only find the cobalt one

I'm guessing the firehouse Shelby is a typical Edison based bulb.

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-Tim
BulbCollector.com
DewCollector.com

rschuett · « **Reply #7 on:** June 19, 2001, 05:04:00 pm »

Well, thanks for the info Tim and to all who have contributed. So here is the question of the day. Why is this bulb burning so long? Are they running it at a significantly reduced voltage? They must be - it is the only way it could have lasted as long as it has. Anyone know the real scoop on this?

Chris W. Millinship · « **Reply #8 on:** June 19, 2001, 07:38:00 pm »

Fantastic looking bulb Tim!

Those interested, my T/H based one can be seen here... http://electriclights.tripod.com/bulbs/thshelby.htm and I also have a little baby sign-lamp sized one not yet on my site, and which needs its base reattaching, but otherwise looks like this...(hooray- I found a way to post pics here again using the web space my ISP provides, that I totally forgot about!)....

Probably made during a similar era to the Centennial bulb. And now you mention it, looking at the closeup pictures, I have to agree it is probably a normal Edison base. The background wallpaper of the bulb`s site shows what looks like a drawing of a Westinghouse based bulb though.

Rick, I`m sure I read on the site that the bulb gets a full 110-120 volts (normal mains)to qualify for the world record. It has lived so long cos it is probably a "freak bulb". Meaning, it might have an unusually pure vacuum and totally airtight stem seals, a flawless filament that is totally free from impurities, maybe its resistance is a bit high or filament length a bit too long meaning it burns cooler too? Just due to the very wide manufacturing tolerances present in those early ones. They got lucky and had a good`un. Probably, equally, there would have been one or two "freaks" off the production line that would have burnt out in weeks or days, but of course those ones don`t get famous. They just get dissapointed customers.

But I suppose, whatever has made it last so long will ultamitly remain a mystery. All that really matters right now is that it`s still a-glowing, and that`s the way I`m sure we`d all like it to stay

[This message has been edited by Chris Millinship (edited June 19, 2001).]

rschuett · « **Reply #9 on:** June 21, 2001, 12:26:00 pm »

Okay guys, I buy the fact that the bulb is probably a "freak" in some way. However, I DO believe it is dimmed. Look at the filament - it is barely glowing. At 100 yrs, it has been burning over 876,000 hours. If you dim a lamp by 50% you increase the life by 20X. At real low dimmed levels, I don't know if any data exists but extending the life of the lamp by 100X might be possible. I think I'm going to give them a call...

Chris W. Millinship · « **Reply #10 on:** June 21, 2001, 03:00:00 pm »

It`s dim because carbon filament lamps like that just are. I read it is 4 watts (or 4cp maybe?), and a 4 watt bulb even today, is dim. Also it appears dimmer on the webcam since there is bright daylight streaming in through the window panels in those doors, and the camera`s automatic exposure compensates for the brightness by turning down. As a result the bulb appears really dim. I looked at the webcam early morning here which is the middle of the night there, dark outside and it looked bright- for a similar reason.

You`re quite right to doubt it- it shouldn`t really still be working but it is. Another reason why it`s still going is the fact that it hasn`t really ever been turned off, aside from being moved 3 times and a power failure or 2 in the early days (it is on the fire station`s backup generator now). Turning bulbs on and off puts extra stress on them since the filament resistance is lower when cold, at least in metal filament types. Thermal expansion and contraction also can cause stresses which could lead to breakages. It`s had an easy life compared to some, couple that with its special unique "freak" charateristics, and maybe just a little bit of good fortune thrown in too (ie being situated away from adverse vibrations or other movements like wind), and you get a famous record breaking bulb.

rschuett · « **Reply #11 on:** June 21, 2001, 03:50:00 pm »

I've emailed the fire co. and asked for their explanation. I'm sure they have had a bunch of "experts" comment on why it has lasted so long. I'll post their response once I've received it..

James · « **Reply #12 on:** June 21, 2001, 03:54:00 pm »

There are 2 other reasons why it could be so dim - firstly, the carbon filament evaporates during operation, and condenses as a dark coating over the glass which absorbs light.

Secondly, because a lot of carbon has evaporated the remaining filament is thinner. Thinner filaments have a greater resistance, which reduces current flow and hence lamp watts. This lamp would probably have drawn 60 watts or more when new, but the website says it is now only 4 watts.

Usually any filament will fail long before it gets anywhere near this thin, because it will have a weak region which turns into a hot-spot, overheats and fails. Perhaps this lamp has an unusually uniform filament, so good that no hot spot has yet formed. I have never come across a lamp which has reduced to such a low wattage level - but carbon filaments inherently contain fewer defects than tungsten, and are less susceptible to hot-spot development so it could be possible.

If this is the reason for its extremely long life, its certainly possible that it may never 'fail'. As more carbon evaporates, the filament will thin further and get colder all the time, thereby further reducing the rate of evaporation. Failure then might have to be declared when the filament becomes so cold that it ceases to generate any usable light.

Hope all this makes sense!

Scott · « **Reply #13 on:** July 02, 2001, 10:26:00 pm »

Yep, discounting a few moves and power failures, the bulb has been on for a century. My guess as to why it's lasted so long-it's running at well below its rated voltage. In an old book I have, it states voltages supplied to homes varies between 32 and 550! Apparently, back in the day, voltage at the home depended on where you got your electricity. Possibly this is a high voltage bulb(200+)run at 120.
When did the 110/220 60Hz AC become a national standard? I'm guessing the late '20's or early 30's. Advertisements for old radios often listed the voltages different models could be used with-usually 32 to 120. I know the old farm wind generators(and donkey engine generators) produced 32 volts,and some older apartments had their own(usually DC)genrators..
In 1976,I built a small nightlight for my aunt in shop class,which is little more than two candelabra(Christmas tree) bulbs in series. It's been on since 1976,discounting power failures. Wirirng a diode in series with a bulb will greatly increase its life,but dim it some.