Hi!
I've got a follow up to a previous posting on lighting P2K locos .....................
I'm fixin to install decoders in several P2K GP7s and GP9s. Installing the decoder is no problem, but the lighting rationale is still not clear to me............
The P2K instructions state to replace the bulbs with 12 volt, 50 ma. Ok, that is pretty straight forward.
While I realize the implication of using different voltage bulbs, I am fuzzy as to what would happen if I used 12 volt 30 ma instead. Would the bulbs burn out, shine brighter, shine dimmer, last longer or shorter than a 50 ma?
While I do have 50ma "in the mail", I also have several new 30ma on hand - but am not keen on experimenting as I don't want to risk a decoder burn out.
Thank you!
ENJOY !
Mobilman44
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
A bulb rated at 12v 30 ma would simply not be as bright. It would not burn out. Since they would draw less current than the recommended bulb, they would pose no danger to the decoder.
They probably wouldn't last any longer than the 50 ma bulb, everything else being equal. If there was any difference, it would tend toward longer life due to running cooler than the 50 ma bulb.
Recovering former former model railroader.
Along with what you have already been told, store the link below and read Lights in DCC. A lot of good DCC info at the site. I refer to his site a lot.
http://www.members.optusnet.com.au/nswmn/dcc_articles.htm
Some put a 22 ohm resistor in series with one light bulb lead to extend the light bulb life. Sometimes a surge in DCC voltage can shorten or burn out a light bulb which is why some prefer LED's. Putting a loco on a friends DCC system that runs a higher DCC voltage can affect light bulbs. Has happened to some as I see this issue in other DCC forums.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Bulbs have an inrush current, the hot filament has higher resistence than the cold filament, thus the 22 ohm resistor to reduce the inrush current so as to not blow out the function output ont he decoder.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
You're better off using the 30ma bulb. It will run cooler and draw less from the decoder output.
Haven' t I seen this thread before?
Springfield PA
Thank you !
I thought the answer was what you all said, but wasn't absolutely sure. Yes, this was brought up in a previous post but it ended up dealing more with LEDs than the bulbs, and I decided to ask a separate question to keep it clearer to me.
My charge right now is to get decoders in those locos I want to keep, and get lights in there that work. At some point I'll probably go in with LEDs, but I'm trying to just keep it simple right now.
Again, thank you !!!
Very well stated.
mobilman44 Thank you ! I thought the answer was what you all said, but wasn't absolutely sure. Yes, this was brought up in a previous post but it ended up dealing more with LEDs than the bulbs, and I decided to ask a separate question to keep it clearer to me. My charge right now is to get decoders in those locos I want to keep, and get lights in there that work. At some point I'll probably go in with LEDs, but I'm trying to just keep it simple right now. Again, thank you !!!
Johnnny_reb Once a word is spoken it can not be unspoken!
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Something to consider in the future, use 1.5 volt bulbs with the appropriate resistor. Those bulbs run a lot cooler.
The link I provided a couple messages ago show how to use them
I use the 12 volt bulbs and the Miniatronics 1.2mm, 1.5 volt bulbs.
richg1998Along with what you have already been told, store the link below and read Lights in DCC. A lot of good DCC info at the site. I refer to his site a lot. http://www.members.optusnet.com.au/nswmn/dcc_articles.htm Rich
Thanks for that link Rich....lots of good info
Brian
My Layout Plan
Interesting new Plan Consideration
In case no one mentioned, don't use 12 volt bulbs in a plastic shell. Some have and a shell start to melt when the 12 volt bulb is right next to the shell. LED's or 1.5 volt bulbs if you want to use bulbs. Some prefer the light from a bulb instead of an LED. Some put the 12 volt bulb in a brass tube. The higher current 12 volt bulbs will be the hottest.
In DC locos, the heat was never an issue as the voltage never got to 12 volts.
With decoders, the voltage will always be 12 volt or more depending on the voltage of the DCC controller.
A 22 ohm resistor is a suggestion I have seen quite a few times.