| Railway Preservation News https://www.rypn.org/forums/ |
|
| Interior light bulbs: Clear or Frosted? https://www.rypn.org/forums/viewtopic.php?f=1&t=26830 |
Page 1 of 2 |
| Author: | Chris Chestnut [ Sat Dec 20, 2008 10:39 am ] |
| Post subject: | Interior light bulbs: Clear or Frosted? |
Hi everyone: I have been looking into the issue of new interior light bulbs for trolley cars for our museum. My understanding is that frosted bulbs did not come out until some time in the 1930s. Most of our cars are from before that period so it would seem to me that we should be going for a clear style bulb. Clear carbon filament edison style bulbs go for around $10.00 per ulb. This is because they are basically being hand made here in the united states. There is an effort to get a special order together right now to manufacture frosted bulbs. The price per bulb will be $2.00 per bulb with a minimum of 3920 bulbs for the production run. I have a quote to do a production run of 5000 bulbs. They will be clear and vacuum evacuated. They will be a compromise of the standard bulb shape and filament , not the edison shape or filament. The price per bulb will be $1.50. My question is, since we are museums, should we try to get as close to the original and go with a clear bulb or jump into the higher priced frosted bulb buy? Is the compromise of the shape acceptable while still giving the light qualities of the clear bulb ok? My own opinion is to go with the clear at this point. I would like to hear from others who are interested and maybe we can get a group buy organized. |
|
| Author: | David H. Hamley [ Sun Dec 21, 2008 11:40 am ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
One thing that concerns me about those Chinese made bulbs is whether they are, or will be, properly insulated for 5 in series service on 600VDC. What distinguished "Street Railway" type bulbs made here was the connections from the base to the filament leads being insulated to withstand the 600V that they'll see when one lamp in a string fails and the full 600V appears across it. Unless insulated for that voltage, there is the possibility of striking an arc inside the base, in which case you can usually kiss the socket goodbye, or risk a fire. Low price is one thing, but any purchaser of the Chinese product had better verify the right specs. And given how many Chinese products have turned up with corners cut and improper qualifications, it would pay to open up a few to check. |
|
| Author: | David Johnston [ Sun Dec 21, 2008 7:01 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
If lamps are to be clear, I would prefer the straight side ("S") lamps. If reprodction lamps are going to be the "A" shape, my preferrence would be for the IF appearance. I agree with Dave about the design specification and quality requirements. There is some real junk that comes out of China. An improperly made lamp in street railway service can cause a lot of damage and be dangerous. |
|
| Author: | toober [ Sun Dec 21, 2008 8:27 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
Is it out of the question to bite the bullet and buy the real reproductions? Yes, the cost goes up, but how many bulbs does the museum need? Being that they are a stock item, the museum could buy smaller quantities, as needed. The bulb makers would love this, and it would help keep the tiny repro-bulb industry alive. Also, might it be possible to contact the people that hand make these bulbs and see if they will do a special order so they can live up to 600 VDC series service? Or extra heavy filaments? And of course, with using real repros gives the museum some bragging rights, for whatever that is worth. The museum's purpose is to showcase what electric railroading was like, and using real bulbs fits right in. Anyway, on Chinese bulbs. It seems like the slightest jostle will break the filaments. Might this be a concern, being placed on a moving trolley car? It would stink buying a whole raft of them, and have one go out every time you go over a frog. Anyway, things to think about... -- Will |
|
| Author: | Bob Davis [ Mon Dec 22, 2008 2:23 am ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
I've been looking at photos of streetcars taken in the 20's and 30's, and they all seem to have frosted type bulbs. Any cars that were old enough to have started out with clear bulbs had them replaced long ago, and relatively few people are left who could remember the "clear carbon filament" bulb days. |
|
| Author: | ebtrr [ Mon Dec 22, 2008 3:01 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
Does traction equipment use 32V DC bulbs like mainline railroad equipment or some other voltage/current type? |
|
| Author: | toober [ Mon Dec 22, 2008 4:11 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
Bob Davis wrote: I've been looking at photos of streetcars taken in the 20's and 30's, and they all seem to have frosted type bulbs. Any cars that were old enough to have started out with clear bulbs had them replaced long ago, and relatively few people are left who could remember the "clear carbon filament" bulb days. What today's public remembers about an artifact (street car lighting, in this case) is not important. What is important is reminding today's public about what the artifacts really were like. In a few short years, incandescent bulbs will be unknown to children. They will grow up with CFLs and LEDs. Would fitting a 1920s streetcar with CFLs and LEDs be right, just because that is what those kids will expect and see in other, more modern light rail cars? No! The point is to make them look at those weird, hot, handmade glass things, and ask "what is that?". -- Will |
|
| Author: | Bobharbison [ Mon Dec 22, 2008 5:21 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
Quote: Any cars that were old enough to have started out with clear bulbs had them replaced long ago, and relatively few people are left who could remember the "clear carbon filament" bulb days. Bob, I know your post is well intended, and I understand what you're saying. However, in my opinion whether or not people remember them doesn't really matter. What should be important is to try and replicate what it was like back then, so folks can see what the artifact looked like when it was in operation. Now I'll grant you that we make all kinds of compromises in railway preservation, and some are justified while others may not be. This may well be another case of the cost justifying a small change that won't be apparent to most people. However, I think the curator should weigh that decision carefully, and decide what's most important. I can tell you that I was recently at a museum that had clear bulbs with old fashioned filaments in them. I noticed them, and thought enough of them to take a couple photos. In speaking with a friend who visited the museum she also mentioned them, and how they gave the car a nice warm glow, almost like lantern light. She's not a railfan, and I really doubt she'd have known what was correct for the car, but she did notice the bulbs and the also nice warm glow effect they give. That's something to consider when making this decision, while most folks won't know whether the car should have clear bulbs, many of them will notice them if you install them. While mostly cosmetic, this particular choice could be more obvious than some to the typical visitor. |
|
| Author: | Bob Davis [ Mon Dec 22, 2008 5:46 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
Point well taken--if a car has been restored to (for example) its 1910 appearance/configuration, the old-timey light bulbs will be appropriate. Regarding operating voltage: During the 1940's Pacific Electric upgraded several groups of cars with "bull's-eye" interior lights, similar to those found in PCC cars. The fixtures were wired in groups of 20 or so, and the bulbs worked on 32 volts each. They had a special feature that would cause the bulb to "short out" and maintain the circuit, keeping the other bulbs lit. (It's not that difficult to find one bad bulb in five, but if it was necessary to locate one in twenty, that's more of a chore.) The big defect in this scheme is that when one bulb fails, the voltage across the others increases by about 5%, putting more stress on the remaining lights. Motormen and conductors have to be alert, and shut off the group with the bad bulb before a "domino effect" occurs and takes out the whole string. The fact that these bulbs are very hard to find doesn't help matters any. |
|
| Author: | JimBoylan [ Mon Dec 22, 2008 7:38 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
The late Tod Prowell of Railways to Yesterday, may he rest in peace, showed me an article in the Electric Railway Journal. It told of Brooklyn-Manhattan Transit Lines using the 1st of what we might now call "P.C.C." bulbs in 1925 in the Triplex 3 section articulated subway trains. These were frosted, gas filled, 30 volt bulbs designed to be used 20 in series and to short circuit from the heat of the 600 volt arc that would be formed when they burned out. The short circuit would shunt or bypass the arc. Before that, Street Railway bulbs were about 120 volts and vacuum, to make it harder for a destructive arc to form. Bulbs brighter than 100 Watts had to be gas filled, so they were specially constructed to be "Arc Resist" for when they burned out when used 5 bulbs in series on approximately 600 volts D.C. Also in the mid 1920s, photos show that B.M.T. was still using the old "straight sided", clear, curly filament bulbs in their elevated cars. However, Philadelphia Rapid Transit photos show frosted bulbs back to at least 1911. The present "Made in China" Aamsco reproduction bulbs may now be gas filled. The one variety of carbon filament bulb still made in America may be vacuum. They may have changed specifications since I asked 2 years ago. |
|
| Author: | Chris Chestnut [ Mon Dec 22, 2008 7:42 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
Well I have been reviewing lightbulb catalogs from 1906, 1915 and 1922 to see if I can get some definite answers. The shape the bulb varied so much that you cannot say what is right or wrong. The shape of the bulb that we all are used to was available all the way back to 1906 as far as I have determined and was probably available even before that. The only real difference was whether it had a tip or not. The issue of frosted or not frosted. Well I find evidence of some bulbs being offered with frosting as early as 1915. It does not appear to be a common option until 1922 at an extra charge for the frosting. The filament seems to be the only real defining point. Carbon filaments were used until a practical tungsten filament was available around the 1910 period. So it really comes down to economics from what I see. Those who have maybe one or two trolleys will be able to afford to get hand crafted carbon filaments at $10 to $20 per bulb. Those of us with fleets have to look at the best priced option. I am probably going to purchase a standard shaped vacuum evacuated clear bulb. I will frost the bulb if needed for the period of the car. I will add a glass tip to the bulb if that is required. at $1.51 per bulb and approximately 20 bulbs per car I have to make decisions that are economically viable for our museum. $30 to equip a car with lightbulbs versus $200 to $400 per car will be the driving factor. |
|
| Author: | JimBoylan [ Tue Dec 23, 2008 11:19 am ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
Ronald Parente, Jim Boylan, and Bill Wall, all at Branford Electric Rwy. - Shore Line Trolley Museum, are trying to find streetcar bulbs. I hope we can trade information, and possibly coordinate purchases. |
|
| Author: | Jim Vaitkunas [ Tue Dec 23, 2008 12:57 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
Ron, Chris, et al: I know you guys are aware of the ARM parts committee e-mail list. This would be another forum for you to announce your intentions regarding these bulbs. Send a note to Rod for further distribution to virtually all the major and minor railway museums. I know a few of us here at our museum monitor the RyPN Interchange on a regular basis, but I don't think our shop guys do. However, they are on Rod Fishburn's large ARM parts e-mail address list for railroad and electric railway parts announcements, inquiries, comments, questions, etc. Thanks! |
|
| Author: | o anderson [ Tue Dec 23, 2008 4:58 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
Trolley light bulbs were discussed recently at some length on the IRMList on yahoo. It seems this post by Julie Johnson makes some significant points and I think it is worth sharing them here: Quote: The major difference in Street Railway lamps vs regular lamps is that in
order to extinguish an arc when the bulb fails there are two features that should be there. First is a high vacuum as mentioned, but more important is the construction of the filament holders internal to the bulb. In the street railway variety, these are in the shape of a "Jacob's ladder" or at an angle to each other so that when a DC arc starts, the arc travels upward to extinguish itself. The old lamp catalogues advises to burn these lamps "base up" (or bulb down) to accomplish this. The same feature applied to the old series streetlight bulbs. In the early days, we at IRM saw more than one time when standard household bulbs were used, in some instances when one bulb failed, it proceed to blow the whole string in succession. In our car 1268 from the "L", incorrect bulbs were used, and when hey started to blow, the reaction was so violent, it welded the bulb sockets to the lamp sockets, destroying them. It has nothing to do with "rough service". It has everything to do with safety distinguishing the arc from 600 volt direct current! In another, a five bulb cluster near the depot blew, and the bulbs exploded glass all over. So you can see his is a safety issue. Cheapen out the bulbs inside a streetcar and you risk exploding the bulbs. Julie |
|
| Author: | softwerkslex [ Tue Dec 23, 2008 6:00 pm ] |
| Post subject: | Re: Interior light bulbs: Clear or Frosted? |
I am unclear on the burnout feature being described. When one of these traction bulbs burns out, it shunts across itself to keep the circuit live? But if cheaply done, it risks a mass outage and arcing? Perhaps it is better to just skip this feature on replacements and endure the annoyance of a string of 5 bulbs dark until the dead one is replaced? Or is this arcing problem still present in any event? |
|
| Page 1 of 2 | All times are UTC - 5 hours [ DST ] |
| Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group http://www.phpbb.com/ |
|