I may have to replace one of my Digitrax AR-1 units with a PSX-AR, but I find the operation and wiring of the PSX-AR confusing.
What I want to do is to create a separate power district for my engine servicing facility which includes a freight yard, turntable, roundhouse and coaling tower. Within this separate power district, there is a small section of track which is a reversing section, requiring an auto-reverser.
As I read the operating manual for the PSX-AR and look at the diagrams, it looks like the two bus wires from the command station connect to the input side of the PSX-AR and two bus wires exit the output side of the PSX-AR and are routed to the reversing section.
OK, so that is the wiring for the auto-reverser portion of the PSX-AR. But, how and where do you wire the PSX-AR to act as a circuit breaker for the entire power district?
Rich
Alton Junction
Rich,
Have several PSX-ARs, but use them only for reversing. Here's what I read as important from the user guide about it's use as a circuit breaker.
First, on page 1 it says that there is "automatic coordination of the auto reverser and circuit breaker tasks."
On page 3, are the connections. The power output is from the J2 section of the board. The PSX-AR comes equipped with one set of outputs, leaving the others blank.
I suspect the extra terminals at J2 is where you'd hook up the section for circuit breaker use, but am not certain. The green screw terminal block should be available, but you can solder directly to the board, too. Then it automatically coordinates which mode it functions as.
Mike Lehman
Urbana, IL
I would run the output wires to a barrier strip. (or you could make a mini buss coming out of the PSX-AR) and then run as many feeders as necessary to all the tracks in the district. The reverser will act as it should in the reversing section and provide protection in the other areas.
There is no separate circuit breaker output. The circuit breaker function acts on the reverser output. Most reversers do not shutdown power if there is a short within the reversing section, they rely on whatever protection you have upstream of the reverser; however, the PSX-AR performs both reversing and circuit breaker functions on it's output. If you want a circuit breaker for the rest of the engine servicing facility, you will have to get an additional circuit breaker for it.
floridaflyer I would run the output wires to a barrier strip. (or you could make a mini buss coming out of the PSX-AR) and then run as many feeders as necessary to all the tracks in the district. The reverser will act as it should in the reversing section and provide protection in the other areas.
That would not work because he would have the reversing section and the rest of the district wired to the same output and the reverser would not be able to reverse the reversing section relative to the rest of the district.
CSX Robert There is no separate circuit breaker output. The circuit breaker function acts on the reverser output. Most reversers do not shutdown power if there is a short within the reversing section, they rely on whatever protection you have upstream of the reverser; however, the PSX-AR performs both reversing and circuit breaker functions on it's output. If you want a circuit breaker for the rest of the engine servicing facility, you will have to get an additional circuit breaker for it.
Thanks, CSX, that is exactly what I feared but expected. The diagram in the instructions shows the circuit breaker as "optional" indicating that the PSX-AR is primarily an auto-reverser with the circuit breaker only a secondary function.
The PSX-AR should work on one of my power districts because that particular power district is one big reversing section.
This is why I said hold off on sending back the PSX's, you still need circuit breakers AND the PSX-AR's for the reverse sections. It's a waste to use a PSX-AR as a breaker for a regular power district, because they cost more and you don;t ned the AR functionality on a regular power district.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker This is why I said hold off on sending back the PSX's, you still need circuit breakers AND the PSX-AR's for the reverse sections. It's a waste to use a PSX-AR as a breaker for a regular power district, because they cost more and you don;t ned the AR functionality on a regular power district. --Randy
Yes, if the whole power district is a reversing section, then you only need the PSX-AR, it will handle the reversing and act as a breaker in case of some other short. Even for your other reversing loops - you don;t feed the PSX-AR from a PSX, you feed the PSX-AR from the main bus. So again trivial example - long straight track with one turnout and your basic balloon loop. You gap both ends of the loop at the turnout. All the straight track connects to a PSX. All of the loop section connects to a PSX-AR. The input to both comes straight from the booster.
The AR-1 would have to come after a breaker because the AR-1 only does the reversing function, if there is a continuous short it relies on something upstream of it to cut the power, either the booster or a different circuit breaker. The PSX-AR does both, first it tries to clear the short by flipping polarity, which is the cause of a reverse loop short. If that doesn;t work, it cuts the power completely, like a regular circuit breaker.
rrinker Yes, if the whole power district is a reversing section, then you only need the PSX-AR, it will handle the reversing and act as a breaker in case of some other short. Even for your other reversing loops - you don;t feed the PSX-AR from a PSX, you feed the PSX-AR from the main bus.
Yes, if the whole power district is a reversing section, then you only need the PSX-AR, it will handle the reversing and act as a breaker in case of some other short. Even for your other reversing loops - you don;t feed the PSX-AR from a PSX, you feed the PSX-AR from the main bus.
I have now bypassed the PSX circuit breakers for the mainlines, so that takes care of 3 of the 5 AR-1s. Then, I took that short reversing section of track in the engine servicing facility and moved its wiring to the mainline, adding a short length of track on either side of the reversing section to the mainline as well to prevent pauses.
So, here is the only remaining potential issue, although I don't think that it will be a problem. When I tap off the mainline bus wires as input to the PSX-AR, will any of the four AR-1s on the mainline adversely affect the input wires from the main bus to the input side of the PSX-AR?
Nope. The only issue you might have with the setup like this is that if there is a short in one of the reverse sections controlled by the AR-1, it will shut down teh booster and thus everything attached.
I am giving some serious thought to keeping all four of the PSX-4 circuit breakers and just adding a PSX-AR to handle the power district that is one big reversing section.
Is there any reason that I could not simply run the output side of one of the PSX-4 circuit breakers directly to the input side of the PSX-AR?
I ask this because the PSX-AR diagram shows a different setup, as seen in the following diagram.
The diagram there is how you should wire it, with a section of the PSX4 where the block is that says "optional circuit breaker"
Reason being, the PSX-AR is also a circuit breeker and doesn't need another circuit breaker ahead of it. Plus cacading the two could result in the exact same problem you had witht he AR-1. In the electronics world this is called a 'race condition' as when the loco leaves the reverse loop there is a race as to which will trip first, the PSX-AR, allowing the train to continue without hesistation, or the PSX upstream of it, causing the delay. With no configuration option to slow the response time of one device or the other, there is no way to configure things so 100% the PSX-AR will react first.
Plus it's a waste of money to have the extra breaker upstreame of the PSX-AR, when the PSX-AR is itself a breaker, with the exact same current capacities as the PSX. Even if the reverse section includes a large yard area where there might be 5 or 6 trains at the same time, the PSX-AR can handle it. Like in some of the recent plans people have posted here asking for help with reversing sections - it doesn;t matter if the reversing section ends up having a passing track and a yard, so long as you cna place gaps such that only 1 train at a time will ever cross the gaps, the reverse section can be as large as you like, and using a PSX-AR will reverse it all when a train crosses the gaps, and should a train derail within the reverse section an short out, it will also completely cut power without shutting down any other part of the layout.
I was just re-reading the PSX and PSX-AR manuals to see how I might use these (with extra components) to get the same sort of feedback I get from the PM42. OK, the PSX's have the 'contacts' for feedback already in them, just need to wire it to a Loconet input device of some sort to get feedback. But the PSX-AR - you have to pay an extra $6 to get the PSX-ARFB to get those contacts. Nearly $60 per reversing section. Yes, you can bet that as many of mine as I can make automatically controlled voa a relay operate by the switch machine contacts, I will be doing so. $5 relay vs a $60 reversing unit, PLUS a couple of inputs off a feedback device (most likely, DeLoof LocoIOs, i can build those for $20/$25 each, and each one has 16 inputs or outputs). With the relay, there IS no short, ever. And no inrush current issues.
Also randomly came across an article on using an industrial quality slip ring for contacts on a turntable, far more robust that the plastic bits on the Walthers unit. Didn't bookmark that, but I'm sure I can find it again.