I have a question about how the AR-1 is supposed to work. Assuming a simple reversing loop whereby the loco traveling in the forward direction enters the loop from the east, travels the entire loop back to the main, picks up some cars from the main then goes into reverse and reenters the loop pulling the cars back through the reversing loop back to the main. I have such a situation where my loco traveling fwd from the east enters the reversing section and everything is good. However once out of the reversing section and I put the loco into reverse and back back thru the reversing section everything is good until the wheels cross the east insulating joiners and a short develops. Should the AR-1 be taking care of this situation or does it only prevent shorts when a train is always entering the reversing section travelling in the same direction, in this case moving east to west. I was wondering if the AR-1 should also make the polarity change for a train travelling back from west to east.
Is there a circuit breaker on the main line? Is the AR-1 being fed by the circuit breaker?
The AR-1 should be taking care of it. There is more to be revealed, either about your wiring or your track plan.
Henry
COB Potomac & Northern
Shenandoah Valley
Semi4 I put the loco into reverse and back back thru the reversing section everything is good until the wheels cross the east insulating joiners and a short develops.
I'm trying to picture how you're operating here. What I'm reading is that you are running forward through the loop OK. Then you put your engines into reverse and effectively push the cars back through the reverse loop and when cars bridge the gap at the far end a short occurs?
http://www.digitrax.com/tsd/KB781/ar1-auto-reverser-trip-current-adjustment/
If the entrance and exit gaps are bridged at the same time the AR-1 won't know what to do. The train has to be shorter than the reverse loop. Metal wheels on cars will bridge the gaps at both ends and a short will result. Is your command station set to auto-reverse? If so they might be conflicting with eachother.
Although it should be obvious, we are talking DCC here, yes? Some folks have tried using an AR-1 on a DC layout.
http://www.digitrax.com/tsd/KB1034/ar1-autoreversing-zephyr-xtra/
Regards, Ed
What brand of turnout is invovled here? If you run out of a reverse loop, then stop the train and back in the same way you just came out, there should be no short, the polarity is already matched for the route you just existed the loop by. You might eb getting a short elsewhere, depending on the type of turnout, on that only manifests when backing through the turnout, particularly if all your cars do not have body mounted couplers as the backing action will tend to skew the trucks.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy, I am just running a loco thru it now, no cars, just to test it out. Yes it is Dcc and I use peco insulfrog turnouts with the stock rails jumpers to the inside rails to elemanate the power routing. I can run the loco into the reversing section ok and it will run the reversing section ok and exit over the insulated track joiners at the end of the section. The problem arises when I back the loco back into the reversing section and travel the full length it will get to the end where the insulating joiners are and as soon as the rear wheels cross over the insulated joiners it shorts out. I am using an NEC Power cab with a cr6 circuit breaker/detector to split out my 6 power districts. Works pretty good and the lights will tell me which district is shorted. I am going to do some meter work to see if I can identify what is happening. I was under the impression that the AR-1 would pick up any short caused by crossing the insulated joiners and change the polarity accordingly no matter which direction.
Semi4 I am using an NEC Power cab with a cr6 circuit breaker/detector to split out my 6 power districts. Works pretty good and the lights will tell me which district is shorted.
My guess is the CP6 picks up the short before the AR-1. Don't change a thing until the gurus report in.
A minor point, this is an electrical issue more than a layout issue. In the layout section of this forum, the layout gurus will comment about your switch back into the yard and your too tight radii. In the electrical section, we love these kind of mysteries, but won't tell you your track plan won't work.
You may have to just adjust the AR-1 a littlemore to get it set just right. That's why it has the adjustment potentiometer.
Big daddy, I knew this was an electrical issue and when I made the post I thought I was in the electronics and Dcc forum. Could a moderatormplease move this discussion to the electronics and Dcc forum.
deleted
Alton Junction
The CP6 is not a solid state circuit breaker. It's a bunch of light bulbs. It's not going to react faster than the AR1, which IS electronic - having a relay does not mean something is not electronic - it still uses electronics to sense the short. It may be slightly slower to break the circuit than a MOSFET which is where the problem comes in when the upstream breaker reacts faster than the relay contacts move, but that wouldn't be the case here, not with a CP6. The CP6 never actually cuts power - it just reduces the short current to whatever the bulb rating is - stock bulbs come on fully at about 700ma which means that even with a screwdriver laying across the rails, the PowerCab should never shut down as there is a maximum of 700ma flowing through the short and the bulb in the CP6. Now, if other parts of the layout on different sectioons of the CP6 have a total of say 200ma going through them (running locos, not a short), x5 sections that's another whole amp so combined with the shoorted section it could exceed the PowerCab.
I still say the AR1 just needs some tweaking. Too far one way and it shorts rather than flips when trains cross the gaps. Too far the other way, and you get a lot of stuttering as it is then too sensitive and tries to flip multiple times when a train crosses the gaps. Somewhere in between is a "just right" setting where traisn move smoothly through the gaps.
Also, make sure the wiring to the AR1 and from the AR1 to the reversing section is the same heavy duty wiring as the power bus. I have seen too many AR1 issues due to the use of bell wire or 22 gauge hook up wire, even though it is 'only' a few feet from the power bus...
Modeling BNSF and Milwaukee Road in SW Wisconsin
First, be sure the reverse section is completely isolated. I struggled for a long time with a similar situation until I worked out that one lead to the reverse section had been wired to a power connection for the main. Also, make sure all four insulated joiners are working properly and preventing any power from either leg of the turnout to enter the reverse section.
If all that is OK, then as suggested, you may just need to get out a small screwdriver and tweak the potentiometer a bit to get just the right sensitivity to get it to work. It' a bit trial-and-error, but usually (if everything else is OK) only takes a few minutes.
Is the engine + cars longer than the reversing loop?
rrinker The CP6 is not a solid state circuit breaker. It's a bunch of light bulbs.
The CP6 is not a solid state circuit breaker. It's a bunch of light bulbs.
Rich
Randy, you were right on the adjustment of the TTL pot. I kept tweaking it down a little at a time until it finally worked exactly as I thought it would. No problem now to enter the reversing loop, exit it and then back all the way thru it. Thanks for the help everyone.