Amongst planning my switch machine mounting I’ve neglected the most important thing…how to power them. I want a fascia-mounted control panel for all my switch machines that is completely independent from my DCC system. I need to know the best way to go from the wall outlet to each momentary switch on my panel. I know how to go from each panel switch to the machine, so it’s just a matter of getting juice from the wall and distributing it to the momentaries. I’m running Peco twin coils…about 30+. …John (soon to be deployed…USS Rhode Island, gold crew, SSBN-740)
Peco twin-coils really need a capacitive discharge system. I have an old (really, like 40 years) power pack that I use for the AC power. That feeds the capacitive discharge circuit, which I built for about $10 in parts from Radio Shack from a circuit I googled on line. The output of the CD circuit is DC. Take one side of that and run it to the center terminal of each momemtary SPDT switch. Take the other side and run it to the common terminal on the switch machine. Then join the other terminals on the switch machines to the other terminals on the SPDT’s, and you’re done.
I got my SPDT switches on-line from Demar Electronics, www.demarelectronics.com for a good price. There are other distributers too. I ordered what they call “commercial grade miniature toggle switches.”
If you mean your standard household wall outlets, the first thing you need to do is drop the voltage with a transformer. The wall outlet gives you 120 volts and you’ll need, at the most, 18 volts.
Your panel switches should have two terminals each, connect a wire from one terminal of the output side of the transformer (or better, a capacitive discharge power supply) to one terminal of each switch. You can run one continuous jumper from one switch to the next. The other terminal for the output of the transformer (or CD power supply) goes to the common terminal of the switch machine. These can also have one continuous jumper. The other side of each switch should go to the switch machine connection that it will control (two momentary contact SPST switches for each switch machine).
For twin coil I use the Atlas slide switch. The nice thing about these is they show the position of the switch. Switch to the left is straight while to the right would mean the switch is open. Just mounted some Kemtron machines on some curved turnouts that originally had the motors on the tabletop. Long engines keep knocking the motors.
The problem I discovered was voltage drop. Originally wired all of my turnouts using 24 gage solid phone cable and used phone style punch down blocks. In order to throw a Kemtron and Peco together I had to up the wire to 18 gage stranded. I use a capacitor discharge unit with a 4700 MF cap. Doubled up on the caps (twin 4700mf) that helped too on the longer cable runs.
It’s also possible to use normally-open pushbuttons to throw two-coil switch machines. The buttons can be mounted on the track lines if your control panel includes a track schematic of the controlled trackage.
Those old Japanese-made rocksmasher two-coil machines (Kemtron and Lambert in US, mine are Katsumi, all the same design) draw a LOT of power. Atlas two-coils are more forgiving, but don’t have the built-in 3pdt contacts.
Ok, this helps a lot, but I have one more question…Is it possible to have a distribution block that splits the wires from the CDU to each switch? I understand that since each switch will be in parallel with each other that current will drop at each split but if I only flip one momentary at a time, there is only one completed circuit at a time so current shouldn’t drop…right? Do I even need to worry about this? The CDU should be able to supply enough current to throw multiple switch machines at once, right? I think that I will use a SPDT momentary vice the push-buttons and I’d like to ease wiring by using a block instead of soldering 30 pieces of wire directly from the main wire from the CDU. Who is a good manufacturer of this distribution block which I am looking for?..John
Yes, you can use a distribution block. The CDU should have plenty of power to drive multiple turnouts at once. Be aware that a CDU dumps all of its charge at once, so you have to wait a short time between throws. On my system, this is typically only a second or two. You can make this faster by adjusting the components you use to build the CDU - different capacitors, resistors and like that.
If you actually wire two turnouts to the same controller, like you might do in a crossover between parallel mainlines, then both will throw simultaneously and you should be fine.
You can get terminal blocks from most on-line distributors. You probably want to look for one that’s designed as a distribution block, with all the terminals pre-wired together. I just bought a bunch of cheap terminal lug strips from Radio Shack and wired the lugs together. Then I solder 3 or 4 wires to each lug. That’s what I use for the lines going out to the turnouts off the CDU. For the line to the control switches, I just daisy-chain the controllers around the panel.