In building my control panel, I will be using two separate power supplies. I will have seven different track sections. I want to connect each power supply through a SPDT switch with a center off (on-off-on). this is easy enough to do, but now the hard part. I will connect the PS's (1&2) to the open contacts on the switch and the track section to the armature. When I flip the switch to either PS, I would like to lite a LED showing which PS is feeding that section of track. I can't seem to figure out how to wire this to turn on only the right LED and not turn on both of them. Is there any help for this newby? Can this be done? TIA Jark
This is an unusual wiring plan. Traditionally in the old-skool DC world, each block gets a DPDT switch with the track connected to the center poles. Then, Power Pack 1 and Power Pack 2 are connected to the outer poles. (Polarity must be observed when connections are made.) When an operator wants a block, they flick the switch toward their Power Pack and the switch position provides a simple visual indication. I know that this doesn't answer your LED question, but I wanted to mention this before you got too far down the track. I'm not at all knowledgeable with DCC systems, so am probably all wet here.
You can use 3PDT toggle switches. Use one switch for each of your 7 track sections (blocks). Use 2 poles for switching between the two throttles (cabs). Use the third pole to switch between either the red or green of a bi-color LED. Use a center off version of the switch you can turn off all throttles to a block. A couple of years ago I did something very similar for one of my Ntrak modules. Photo below.
If you have no reverse loops now and never will have any reverse loops in the future, and you can guarantee the two power supplies are isolated, and you have the forwards/reverse switch on each throttle before the block switches, you can connect one output of each throttle together and to the common rail; then a spdt switch can feed the gapped rail from either PS1 or PS2. If you wire it wrong, smoke or flames may result, hence why most people gap both rails and use a dpdt switch which just reduces the options for problems. Following this vein, a third contact running the LED is also the simplest approach - a 3PDT centre-off switch, as suggested already
Jark I just remembered that I had a drawing for my little control panel and thought it might help to explain how this can be wired.
