|
|
Post by q8 on Aug 18, 2005 19:19:57 GMT
 Now the old "R" stocks had fluorescent tubes installed for passenger lighting. These were non-standard 2 ft tubes and they had an odd quirk. When you pressed the lighting trigger switch to turn them on they lit up instantly WITHOUT STARTERS. If it was very cold however they would dimly glow for a while before giving full light. Now how was this done? Tube staff try to let our non rail mates have a go first.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Aug 18, 2005 19:58:56 GMT
oil lamps?
|
|
|
|
Post by q8 on Aug 18, 2005 20:05:31 GMT
oil lamps?
------------------------------------------------------------------------
Har f*ckin' har !!!
I may be ancient but I ain't THAT ancient
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Aug 19, 2005 7:52:01 GMT
Wood burning fires?
Sam ;D
|
|
|
|
Post by redsam on Aug 19, 2005 19:07:56 GMT
condensation on the elements of the tube?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Aug 19, 2005 19:40:56 GMT
I'd guess something to do with the gas [or whatever it is] inside the tube?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Aug 19, 2005 21:00:42 GMT
aint it got something to do with a metal strip down one side of the tube to help it strike as im sure electronic starterless chokes were not invented then
|
|
|
|
Post by zman on Aug 24, 2005 0:47:41 GMT
Flourescent tubes emit less light when temperatures are around the freezing mark. A flourescent light will increase to normal polarity if given the chance to warm up, however if the temperatures remain bitterly cold, the flourescent tube will not be able to acheive full polarity.
Take for example my avatar on the left. You can see that the station is properly lit by flourescent tubes. If the station were to be around 20°F (about -7°C), the tubes would only reach 40% to 50% polarity giving the station an appearance of being only halfway lit.
Thus the dim bulbs when the cars were cold.
|
|
|
|
Post by q8 on Aug 24, 2005 1:35:08 GMT
Well thanks for the xplanations lads. The reason was that the voltage was 115v AC but the CYCLES were 800 and not your average 50.
|
|
|
|
Post by russe on Aug 24, 2005 12:00:14 GMT
Many fluorescent tubes operate without starters. The reason those tubes came on immediately was the style of pre-heater circuits, together with well-engineered matching chokes with adequate capacitance. The frequency of excitation is substantially irrelevant to the basic operation of a tube, although it has a bearing on its efficiency (lumens per watt) and of course its flicker characteristics. The excitation frequency does however have a very significant effect on the RFI emanating from the wiring between the tubes and their ballasts, and this is often the determing factor for the choice of frequency.
Russ
|
|
Phil
In memoriam
RIP 23-Oct-2018
Posts: 9,473
|
Post by Phil on Aug 24, 2005 13:28:55 GMT
Q8, as usual you are a star! You've solved (I think) something which has been bothering me for years. At the National Grid headquarters in Gloucester their conference rooms have fluorescent lights which can be fully dimmed out AND then brought back up again. They would never tell us (scientists) how it was done, simply saying 'We all know that's impossible don't we?', which it is with normal 50Hz mains. High frequency is almost certainly the answer to this, so you've made me a happy fella.
BTW I did know about the 850Hz supply from Steam To Silver but never made the connection to the starting characteristics.
supposed scientist crawls away in shame
|
|
|
|
Post by q8 on Aug 24, 2005 18:10:29 GMT
There was another little oddity with "R" stock tubes too. Sometimes the light in the tube could be seen going along in "waves" I dunno why though.
|
|
|
|
Post by piccadillypilot on Aug 24, 2005 18:27:10 GMT
Sometimes the light in the tube could be seen going along in "waves" I dunno why though. Perhaps it was simply pleased to see you? ;D |
|
|
|
Post by cajim on Aug 24, 2005 21:41:17 GMT
Dimming fluorescent lamps have been standard for some time. Here is one that is in 110v and 220 v.
Dimlite
Luxlite Dimlite is the new series of dimmable compact fluorescent bulb. This product is suitable with ordinary incandescent dimming circuit so no changes necessary in your fixtures.
Dimlite is energy star tested and ideal application is table lamp or reading lamp.
Diming range for Luxlite dimmable bulbs are from 100% to as low as 10% to 0. Available in both day light or warm light colors with E26 medium base for 120V version or E27 for 220V
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Aug 24, 2005 22:15:30 GMT
There was another little oddity with "R" stock tubes too. Sometimes the light in the tube could be seen going along in "waves" I dunno why though. The tubes on D stocks sometimes do that. |
|
Phil
In memoriam
RIP 23-Oct-2018
Posts: 9,473
|
Post by Phil on Aug 25, 2005 9:19:27 GMT
Dimming fluorescent lamps have been standard for some time. Here is one that is in 110v and 220 v. Dimlite Ah So, those clever Japanese! ;D ;D ;D ;D (just looked at their website) |
|
Now the old "R" stocks had fluorescent tubes installed for passenger lighting. These were non-standard 2 ft tubes and they had an odd quirk. When you pressed the lighting trigger switch to turn them on they lit up instantly WITHOUT STARTERS. If it was very cold however they would dimly glow for a while before giving full light.
