I have a Digitrax AR1 Automatic Reverse Controller which I've been told can also be used to control polarity on a turntable. Can anyone tell if this is true and if so, is there anything special I should know about installing the product? The Digitrax instructions do not address this option.
Set your font to monospaced to read the diagrams more easily.
For DC***: Main rev.^ switch-> rev. loop rev. switch > rev. loop or T/T |> rest of layout
For DCC:
1) with single booster: Comm. station -> DCC bus (booster) -> aut. rev. unit -> rev loop or t/t |-> main layout/power district
OR:
2) with two boosters Comm. station -> DCC bus (booster) A -> main layout/power district |-> DCC bus (booster) B > rev. loop or t/t
A rev. loop changes the loco's direction from "eastbound" to "westbound". A t/t changes the lcoo's direction from "inbound" to "outbound." In either case, it will still move "forward."
For an oval main line, it's easier to think in terms of "clockwise" and "counter clockwise". ****
NB that on a DC layout, it's easiest to wire the t/t itself to act as the reversing switch. I'm not sure if this will work with DCC.
*** To reverse the train's direction on a reverse loop, set both rev. switches to east- or westbound, as the case may be. While the train is in the rev. loop, set the main rev. switch to west- or eastbound, as the case may be. BTW, there are detection and relay circuits that will do this automatically.
**** Because the typical 4x8 is operated from outside the loop, the inside rail of an oval is the "North rail" (or grouNd), and the outside rail is "South rail" (or hot/power rail.) These designations matter when attaching feeders.
A train travelling counter clockwise will pass from west to east on the front track of the layout, so eastbound = counter clockwise, and westbound = clockwise on such layouts. But of course you are free to designate east- and westbound according to your operating needs.
Feed the reverse controller from the same booster which is feeding all the other turntable tracks. Then feed the output of the reverser just to the turntable table itself.
Yes, works equally well with DCC and since turntables are normally designed to work with DC you may as well use the built in switching and save the expense of an auto-reverser. Keith
A reversing loop will connect an S,N to N,S where it rejoins the main line, which causes a short. So you must gap both rails at each end of a reverse loop. The track between the gaps is the actual reversing section.
If you trace the N,S rails on your track plan, and find that at some point an N connects to an S, or vice versa, you must gap both rails, and trace back to some convenient point to put in the other pair of gaps. This section of track will be a reversing section, whether or not it loops back. It must be at least long enough to hold your largest engine or consist. The gapping must be done regardless of the control system you use.
It's possible to create reversing sections without realising it, so study your track plan carefully. Watch for cut-off tracks, or crossovers between main lines that are parallel for a short stretch, and so on. It helps to run an imaginary train over all possible routes. (Some layout design programs include this facility.) If you find that you are passing some point in the opposite direction, you passed over a reversing section somewhere. I speak from experience: I've designed some fairly large layouts in my time, and have occasionally found unexpected reversing sections.
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