DCC is AC power right? That should mean neither rail has a + or - charge or am I just dumb?
I took this to K-10 trains to show him my new idea to join the new bench to the old.
He drew in the other rails and said that I must change the polarty of the new bench. Lets say on the old bench the out side rail is +. On the out side rail of the new bench must be -.
My DCC unit does not show + or - on the power leads. If I flip them around the train still goes the sameway?
Confused again Cuda Ken
I hate Rust
Ken, leaving alone your Bud's analysis for now, the decoder gets an altered AC current, but it converts the current that it apportions to the motor to DC so that the motor, which is a DC can motor, can deal with direction changes itself, and not through a series of gears in the transmission as your Cuda does....Ken.
Now, about the polarity thing per your Bud's analysis, I don't see it. If you wire each loop with a red wire feeder going to the outside rail and the black going to the inside rail, even at the crossover you maintain that orientation, and the loops never change anyway. So, your DCC controller will know if you cross wires just as a lightbulb will. Circuit breakers everywhere will pop.
AC or DC is not the issue. If you run a loco from the old to the new: the wheels on the outside of the old will end up on the inside of the new loop. If you gap the crossover; you will have a short when a metal wheel hits the gap unless you wire the new loop to have the same wire on the inside as the outside of the old loop.
Just wire the new loop so that the right side wheels of your loco's get power from the same supply wires as they do from the old loop.
Ken, DCC is AC power, and that just means the plus and minus charge on the rails are constantly changing places, many times each second. You just want the train to get the same charge to the wheels as it goes along the track - everywhere. Keep the red wire on the right wheels, and the black wire on the left wheels. You don't need any gaps unless you have a reverse loop or somthing similar.
(However, some crossovers will give trouble with shorts when the train goes through them. But this is a different problem. I fixed mine by insulating with a few small pieces of masking tape)
Yes, K-10 Trains is right. If the red wire goes to the outside rail on the old layout, then the red wire should go to the inside rail on the new layout.
Also, it is comon usage to call the red wire +plus, and the black wire -minus. Not exactly correct but it simplifies the thought process. And by the way, you can run several trains in different directions at the same time. That's one of the advantages of DCC!
-Bill
There isn't + and -, per se, but there are two wires, and you can't short them together. So, call them A and B, if you want. As you go through the double crossover, if A was on your left going in, A has to be on your left coming out. So, whichever wire is on the left side on the original loop, must be on the left side of the new one. Based on what it looks like is happening in your drawing, that means the wire that is on the inside of one loop in on the outside of the other.
Jeff But it's a dry heat!
Thanks for the answers folks, just wanted to double check.
Cuda Ken
ndbprr wrote:There is one case where it is very important and that is on reverse loops. When the engine reachs the main track again the sides are reversed and a short occurs. You need a module most maufactirers offer that will auto switch the reverse loop when this happens. apparently there is no lasting effect from the instantaeous short it detects and corrects.
The rules are the same whether it is DC or DCC, though we might use different words. You don't want to short the two rails together. Reverse loops (or more generally reversing sections, which can look to be other than loops) are the obvious place where this is a concern. In the case we are looking at now, powering the frogs in the center of the crossover can be another place where an autoreverser can be used. I've seen a diagram, I can't find it right now, I'll look it up later.
wjstix wrote:Remember Lionel trains run on AC - and on three rails to avoid reverse loop short circuits!!
One could do the same with DC, if one was willing to accept the third rail.