Accesory wiring

[jecorbett]

I have a large DCC layout using a Lenz system. I use the Atlas Generator from my original DCC system for track power. I have a bank of switches for turnout control and lighting on the opposite side of the room from my power supplies. The turnouts and lighting on the side of the layout with the power supplies are wired to an old MRC power pack but to run wire from the bank of switches on the other side of the layout would require running about 40 ft of wire around the room under the layout. Rather than run all that wire, I was thinking why not just tap into DCC bus wires since they provide constant track power. Does anyone see a problem with doing it that way?

[simon1966]

I wouldn't do that, you will be sucking power from your track and may max out the booster more quickly.  Just get another power supply for the other side of the layout room?

[retsignalmtr]

i tried that with my digitrax empire builder. didn't work. when connected to the dcc buss the switch machines just buzzed a little but didn't move. but when i put the switch buss right to the power supply they worked fine. the stationary decoders that operate the switches on dcc have built in capacitor discharge units which supply more power to the machines. so i'm just using the dcc power supply to operate my switches before it goes into the command station. we do this on my clubs layout too. also it doesn't affect train operation either. 

[Vail and Southwestern RR]

The amount of current available from the DCC bus is probably not sufficient to drive a "snap" type switch machine.  I wouldn't be too surprised if some command stations might even decide it was a short.  On the whole, it isn't a good idea, as you discovered.

[tomikawaTT]

Since I use twin coil machines, I prefer to keep them (and their high surge currents) divorced from running power.  My solution to the 'long wire to the switch' problem is to use a single wire and four cheap diodes (two at each end of the single wire) to throw the switches - the coils are polarized and switch machine power is AC.  That reduces the wiring required to one wire to each switch machine plus a single common return bus.

Since, when bought in quantity, a diode costs about as much as two feet of single-conductor wire, there is a considerable monetary saving, as well as a considerable reduction in cable diameter.

Chuck (modeling Central Japan in September, 1964)

 

[jecorbett]

OK, you've all convinced me. Thanks for the responses. I'm always looking for the cheap and lazy way to do things. Apparently that approach isn't a good idea in this situation.