I am having problems with shorting on my ho scale layout. It is powered with the DB150 and i have two loops upper and a lower that i use psx-ar’s connected to turnouts. The problem i am having is the train or cars will short the system and it beaps for a second then everything powers back on engines and all, but the psx-ar’s are throwing the turnouts and sometimes i have a train going through the turnout and it switches and causes my cars to derail. Do i need to turn up the trip on the psx-ar’s or the DB150 or does this sound like a whole different problem than that? The trains run fine till something shorts them usually happens on turnouts it seems. Also could you explain what the trip settings do? i know the psx goes by amps all the way up to like 15 or something but what exactly does that mean. Thanks still trying to figure out all this dcc.
Are you talking about the normal action of the PSX-AR when a train reaches the other end of the loop and the reverser is supposed to flip the loop polarity, or are these shorts caused by something else?
The two PSX-AR units should not be connected to each other - no daisy chaining because one loop is inside the other. Without a track diagram, I can’t tell if that’s the case, but such an arrangement would result in the two units “fighting” each other over polarity.
no, i dont have them connected together. I have them in two completely different loops. My layout is a double decker with a helix to go from one deck to the next. The problem is caused by another train maybe going through a turnout in anothother part of the layout and triggering a small short which causes my DB150 to beep twice and then power back up. The psx-ar reacts to the shorts which in turn will actuate the turnout of the mouth of the loop. If a train is going through one of those two turnouts it causes derailments.
Mr. B is right. We need to know more about the track arrangement and how you have the PSX-AR’s hooked up.
I’d add that know more about where the loops are gapped in relation to the turnouts would help, too. I have a suspicion your gaps are too close to the turnout or the trains you’re running are longer than the gapped section of the loop - or at least too long in relation to their speed in approaching the turnout before it throws.
I agree, it sounds like the gaps are too close to the switches.
Are the switches DCC compatable?
The only short the PSX-AR should react to is one in the section it controls. If a short occurs upstream it will power off, but it should act like it was shorted.
You probably should have some regular circuit breakers for the rest of the layout with nothing driven directly off the booster.
–Randy
I’d recommend that, too. What’s happening is that the DB150 is completely shutting down, killing all power to the input side of the PSX-AR. It must then reset, and it appears it has a default position for the turnouts on power-up. I don’t have a PSX-AR myself, so I don’t know if that’s true. OK - I looked it up. CV52 sets the direction of the controlled turnout on power-up, but there is no option for “leave it the way it was.”
If you use a separate breaker (or breakers if the layout is large enough to divide into districts) then those other shorts will be handled by that breaker, not the DB150, and the PSX-AR’s will not reset.
Is it possible that the DB150 is acting like an auto reverser, too, and conflicting with the PSX-AR?
You can change option switch 3 to make the DB150 NON auto reversing which would probably be a better choice if you are using downstream auto reversers.
http://www.digitrax.com/tsd/KB266/db150-option-switch-table/
Just a possibility to explore, Ed
I am wondering the same thing.
I did some research on this problem, and I noticed that the OP has started several threads on this and related issues over the past 3 or 4 years. If that is correct, then this has been an ongoing problem, never quite resolved.
I have several PSX-AR units on my layout, and they work just fine. But the key, as Randy has mentioned, is to let the PSX-AR handle the short caused by reverse polarity without interference from other competing units. In other words, the PSX-AR requires direct power input from the main bus and should not be connected upstream to other circuit breakers or other auto-reversing units. And, as Ed suggests in the preceding reply, if the DB150 is also acting as an auto-reverser, problems and conflicts will occcur.
Before messing with the trip current settings on the PSX-AR, I would take a closer look at the placement of all gaps that isolate the reverse loops and at the sufficiency of feeders inside the reverse loops. The default setting on the PSX-AR is 3.81 amps, and that default setting should work just fine when preceded by a 5 amp booster such as the DB150.
But, the bigger issue is the placement of the PSX-AR in relation to the DB150. If the DB150 is set to act as an auto-reverser, that would seem to be the problem. The PSX-AR is both a circuit breaker and an auto-reverser. No other circuit breaker or other auto-reverser should be in-line in front of the PSX-AR. The
Randy’s suggestion will solve the problem as described. Everything is actually working exactly as it should be. But, when a short occurs elsewhere on the layout, NOT in a reverse loop, the DB150 shuts down. Since the PSX-ARs are powered by the DB150, they shut down, too. When they power up, they throw the turnouts they control to their “power-up default” position, which may be different from where they were, thus derailing trains which may be on them at the time. The key is to put another breaker (non-reversing) between the DB150 and the track so that breaker handles all other shorts and the DB150 itself never shuts down.
Now, sir, why are there shorts occurring elsewhere on the layout? Do they happen on Peco turnouts, by any chance?
My understanding is that if you put a PSX-AR downstream from another circuit breaker (say, a PSX), you will create a conflict.
Rich
I suspect it is a bus wiring issue as people surmise. If that is the case, add a jumper around the other units and temporarily power the PSX-AR directly from the booster/command station. If the problem goes away, then consider a permament rewire to resolve the problem.
BTW, I think I’m correct in saying that in general, not just in this particular case, it will avoid mysterious problems, by wiring all circuit breakers to the bus without passing through anything else. With auto-reversers, not all include a CB like PSX-AR does, so those would be the exception. If a CB is included like on the PSX-AR then it, too, needs a direct uniterrupted feed.
Correspondingly, if you have parts of the layout that are fed directly, but which do not have a CB, when they cause the booster/command station to trip, they would essentially cause the same symptoms if you have a PSX-AR. I ran across this when my DCC was new, as I tried to cheap out with fewer CBs, but making sure all track is protected by a CB ensures that when there’s a short, only the affected power zone goes down.
If the other breaker is non-reversing, you won’t get a polarity conflict, but you may need to adjust trip currents so the “right” device handles shorts.
In general, though, you should not daisy-chain breakers or auto-reversers. They should all come directly off the booster or base station, and in an ideal situation the booster should ONLY be connected to tracks through either a breaker or an auto-reverser. The trip current for any of these should be set lower than the booster so that the booster itself never has to handle a short and should never shut down.
I was not referring to a polarity conflict. If you place a circuit breaker, such as a PSX, between the booster and the PSX-AR, the PSX may trip without shutting down the booster, resetting the PSX-AR in the process.
Let’s say, the PSX-AR is left at the default trip current of 3.81 amps. The DB150 is 5 amps. So, the circuit breaker between the PSX-AR and the DB150 has to be somewhere between 3.82 amps and 4.9 amps. But, the closest settings for the PSX trip current are 3.81 amps and then 5.08 amps.
The other problem is that the DB150 serves as both a booster and an auto-reverser, so if the PSX-AR is downstream, it would seem to me that the auto-reverser function has to be turned off on the DB150.
Rich
It does make sense if the auto-throw feature of the PSX-AR has a ‘default’ position that it will alsways move the Tortoise to when it powers up - if it happens to be thrown the other way due to the last train through the loop and it loses power because the booster feeding it drops, then when it all powers back on, the switch will be set the wrong way.
If the rest of the layout were also protected with a seperate breaker, thsi wouldn;t happen. Ideally there should probably be multiple power districts ot eh main, as this sounds liek a fairly large layout. But even just one PSX unit, between the DB150 and everythign ont he layout that is NOT connected to the PSX-ARs, would do the trick. The output of the DB150 would go ONLY to the PSX-ARs and the PSX. A short ont he main would not affect either PSX-AR. A Short in the loop would trip that one PSX-AR but the main and the other loop would be unaffected.
–Randy
i know what your talking about and the gaps are about a foot from the mouth of the turnout. The whole bottom of my layout is the reversing section so it’s not the trains being too long. The whole top is also a reversing section. I have a helix that seperates the two reversing sections. The turnouts are being thrown in time.
Thanks, ill check opt. switch 3 to make sure it’s not in autoreverse mode.
I must have lead you guys wrong somewhere. I dont even have a psx just two psx-ar units. One for the top and one for the bottom. I only use them as auto-reversers. The DB150 is my command station for my whole layout. The short will happen even if the train is within the loop. i have them both set at 3.81 amps.
After reading all of your threads. I have come to the conclusion that you guys all have a dizzing intelect. I am going to draw a whole diagram of my layout and the wiring and then we will see what all you dcc geniuses think. Maybe you could give me some good ideas on wiring it a little more bullet proof. You all know that its more fun to run trains when they run alot more flawless.[swg] Thanks for all your input on this subject. I should repost shortly with a diagram.
So the 2 PSX-AR provide protection (and reversing) to the loops only?
And they are the only protection, other than on the booster itself?
Then the first thing I’d do is get a 3rd breaker to protect everything except the loops. Wire so that each of the 3 (2 PSX-AR and the new, 3rd CB) gets power directly from the -150. Then see if the problems go away. This may not completely solve things, but should improve them.
If cost is a problem, it is possibe to wire one PSX-AR to cover both loops so long as no more than one train at a time moves into or out of BOTH loops. Then the other PSX-AR can be set to be a circuit breaker only (I think this is possible, but it’s been awhile since I looked at the docs) for the rest of the layout?
Note that running two reversing sections on a single PSX-AR is less than ideal. It did work for me for a year or two until I was able to upgrade and add a second PSX-AR for the other reversing section.