I wonder how well some of the computer pwoer suppykl stuff would work on the newest power supplies (which in a few years will be the surplus ones we can get for cheap or free). Old power supplies that we pick up now, they direvied each voltage independently so you can connect them together to get the different combinations. The newest ones, particularly the high power ones to drive the leatest graphics cars, ar relaly little more than a high capacity 12V power supply with some regulators to produce a few other outputs like the +5 and +3.3. Combining them may NOT prodce the desired results.
Of course, you cna just think of one as a greta big 12V power supply, 50+ amps (DEFINITELY use fuses and multiple circuits here! This is welding machine territory.) and run a 12V bus around the layout and tap odff with smalle circuits using voltage regualtors where somethign other than 12V is eeded - a typical regulator and the filter capacitors it needs, with a small piece of circuit board to mount it, will cost under $2. This way you don't have to run various fixed voltage busses under the layout because over on one corner you have a workign traffic light system that runs on 5 volts and over there the streetlights all have 16V bulbs in them so they need 12V, and so on.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I like to use old recycled power supplies from computers for several reasons:
Power supplies from computers are typicall UL listed, grounded, supply regulated clean voltage. (And best of all they are cheap, and you are recycling!) They provide +12V, -12V, +5V, +3.3V, and ground connections. You can also get 8.7V, 7V, 1.8V, and a small current 24V with NO additional components. It's super easy and if you need explination how to easily do this, please let me know.
This is the pin out on a typical ATX power header from a computer. To turn on the power supply, short pins 14 and 15.
http://pinouts.ru/Power/atxpower_pinout.shtml
Each 4 pin connector also supplies Ground, +5 and +12 Volts
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
I use 16-volt bulbs, but I only run them at 12 volts. That reduces their brightness, and I prefer the lower level and the "warmer" glow. It also greatly improves the life of the bulbs. I use the Walthers Cornerstone street lights, which have 16-volt bulbs. The bulbs are NOT replaceable, so once one goes, you need a new light. So, extending bulb life becomes very important. Likewise, if you build bulbs into your structures, replacing them can be a significant job.
I also like the idea of breaking down the load, either among multiple power supplies or from a single one. Besides fuses, I also have toggle switches. This lets me selectively turn on the cheap, easy-to-replace building lights while saving those expensive streetlights for "special occasions."
I generally figure about 30 milliamps for each of these small bulbs. It's amazing how fast those milliamps add up, though. If you don't keep track, you're likely to put too many bulbs on a circuit, and blow the supply. Most of these "wall-wart" supplies have a simple, built-in, non-replaceable fuse to keep them from burning down your house, but once you pop that fuse, you'd might as well find the appropriate method of recycling old power supplies with your local Department of Public Works.
It takes an iron man to play with a toy iron horse.
They're 12 volt at pretty many amps, so they shoudl work fine as long as your street and structure lights are designed for 12 volts. I'd also connect the output to a small piece of perf board and install a few fuses to make up multiple circuits. Base it on the transformer rating, if it puts out 12V at 3 amps, break it into 3 circuits with 1 amp fuses or circuit breakers. If it's 12V at 10 amps and you don;t need all 10 amps, hook up as many 1 amp circuits as you need. This will keep the full power of the transformer out of the relatively thin wire used for small light bulbs
Maybe this has been covered before on here but Im wondering has anyone ever used a low voltage landscape transformer for lighting there layout. I am in the planning stages of a 16x20 layout and I like to light most of my structures and streets and this layout will also have a carnival so I will need several small tranformers or something larger. Im sure I have a couple of the low voltage tranformers and Im wondering if anyone has tried these before?
Dugan