DC Power Supplies

The layout needs a number of power supplies for different things. These are connected to several busses. The bus wiring and power supply sizing are described on the Wiring Design page. This page describes the power supplies themselves.

DC Command Station & Booster Power

I bought a Digitrax PS2012 power supply, which provides four outputs of 5 Amps each at 12 Volts DC (and various other amounts if set to other voltages). One of these is used by the DCS100, and a second is available for future use by a booster (which doesn’t look very likely at present). I’d planned to use the other two for accessory power, but that idea ran into a number of problems, and in the end I used one output for a variety of accessories, but had to create separate supplies for a couple of others. The fourth output of the PS2012 is at present unassigned.

Lighting Power Supplies

My LED lighting power supplies are voltage-regulated 1.5 Amp, 12 Volt DC supplies (“wall wart” transformers) using the same 2.1mm output jack as the PS14. These aren’t fused, and short circuits are very likely with all of the wiring that will be connected to them, so I built a simple little box that converts each jack to a pair of binding-post terminals, and includes an inline fuse (I couldn’t find a 1.5 Amp circuit breaker). I’m starting with two of these supplies, but I expect to eventually add more (a third for the “village” area seems like a good idea at a minimum).

Note: I’ve decided to move the lighting supplies over to the new fuse box I built for the PM42 and other systems, described below. I’ll keep this one, and may re-use it on the tram layout, or on my workbench.

DC 12V Fuse Box 2131
Fuse box for two 1.5A supplies (although the two jacks on the back appear to be both wired to the right set of binding posts, that’s an illusion due to the angled view). The two halves are independent jack/fuse/post sets.

Circuit Diagram for Fuse Box (power supply is external wall-wart)

PM42, Occupancy and Signaling Supplies

I eventually decided that I needed several power supplies for the PM42 circuit breakers (12V) and the BDL168 occupancy detectors and SE8C signal controls (15V). Again I mostly used regulated “wall wart” supplies (the current PM42 supply is a larger 2 Amp bench supply, but I may replace it). For that, I was going to need another fuse box like the one I did for lighting, but this time I decided to make a larger one that I could add more fuses to in the future. So I bought a metal kit box (ironically, soft metal is easier to drill large holes in reliably than plastic) and drilled it for eight input/fuse/output sets. Most of these are designed to work with a 2.1mm jack power supply (the most common form), but I made two with a third input hole so I could use binding posts on the input instead of a jack. This allows me to run some other kind of supply (like my bench supply) through it it can use wires with spade lugs (or even bare wires).

DC Power Box I - planning 3588 DC Power box II - drilling 3589
Planning and drilling the DC fuse box (leather gloves are a necessity - sharp metal cuts very easily)

DC Power Box III - wiring 3590
Wiring inside the box - positive through the fuse, negative straight across

Note that there are four sets of binding posts on the output side, but one set isn’t wired. The store ran out of fuse holders. I only need the three wired up for now (PM32 on left, and two BDL168 supplies to the right of it).

DC Power Box - front 3592 DC Power Box - rear 3591
Output side (left) and input side (right)