I am unable to figure out how to wire the 1156 bulbs to my ho layout. I am using a Digitrax Super Chief 8 amp system. I have 1 loop main and will be adding another loop once the first one is up and running. I have the 2 bus wires run, the feeders soldered to the rail and dropped down under the layout. I do not have any switches at this time. I know the wiring is simple and I am making it way more difficult then it needs to be. I have searched the internet but I cannot find a diagram or a description that explains it so that I can understand it. I am using scotch locks to connect the wires up. I have created 18 power districts and I would like a bulb wired to each district. Can someone explain in plain English how I attach the bulbs to the power districts? I do not plan on running more then 5 engines at a time for now. You can't imagine how much I appreciate your comments.
My railroad, my rules!
With 18 power districts you would have to use 1 bulb wired in series with each of the wires that feeds each individual power district. Are you using the feeders to create the power districts? Have you gapped both rails for each district?
Attach one wire from the bulb to the DCC buss and the other wire from the bulb to the feeder of the power district.
What size is your loop of track? 18 power districts may be overkill. Maybe not for an entire layout, but for one loop?
You need to conenct all feeders for a given section together - consider it a short bus section. One of this sub bus's wires goes to your main bus. The other wire connects to the base pin of the light bulb. The side of the bulb is connected to the other main bus wire.
See here: http://www.rr-cirkits.com/Notebook/short.html
there's an extra piece used ere to make this a more current limited situation - the 1156 bulb by itself still allows about 2 amps to flow through any short circuit and this is why I do not like this method. Those that use it and have no problems I suspect would have no problems without the light bulbs either. My previous layout ran as all one power district and I had no problems. Dick Bronson's modification causes each district to handle up to 2 amps, but if there's a short it will limit the current to under half an amp.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Yes the rails have been gapped. I am using flex track for my straight pieces. Each piece of flex track has a feeder wire and is it's own power district. I read that when using the 8 amp system that the more power districts the better and wiring each piece of flex track was a good rule to follow.
I think that a power district every 30 inches is overkill. What is the size of your loop? Depending on it's size you probably only need four.
It sounds needlessly complex to me.
I am not a fan of the tail light system. Circuit breakers are a better idea. On a single loop, the circuit breaker built into the command station is all you need. On large complex layouts, separate sections, each with it's own breaker, keeps a derailment from shutting down the entire layout. In a single loop, I WANT a derailment or short circuit to shut down the entire layout.
Dave
Lackawanna Route of the Phoebe Snow
Each loop will be 8 x 22. It seems to me the more bulbs I have the easier it will be to trouble shoot. Since I am new at this though I really do not know.
You aren't making power districts. You are making powered sections that are gapped. Each of those power-gapped sections gets a bulb. Wire the bulb in series into one of the sub bus wires feeding each gapped section,
It goes like this: two wires of a hefty gauge off the power source terminals eventually have a pair of sub bus wires cut into them to supply the closest gapped section of rails. Into one of those two sub wires goes the bulb.
You have two loops. Break each loop into halves or thirds or quarters...your choice. Now that each needs its own power supply, you can sub-bus each section with just the pair, or use the pair to cut off several feeder pairs. For those of us who don't trust joiners, we solder feeders to every second joiner pair. That guarantees two fed lengths running away from each soldered joiner pair with feeders.
Crandell