Hi,
I've got two DCC Specialties PSX-4 breaker sets on my Digitrax SuperChief HO layout - one breaker for each of 8 power districts.
I believe that they may be set too low, having tripped them twice in the diesel engine terminal district - which at the time contained 10 or 12 power units with 8 sound units.
In attempting to understand the directions, it seems the default is at 3.8 amps. I think I would want them to be at 6.3 amps (calls for a jumper), which is the next choice. This which would solve my problem - I think.
Obviously I don't fully know what I'm doing here, and wonder if anyone out there can give me some advice and/or guidance in the matter.
Thank you,
Mobilman44
ENJOY !
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
You don't say what command station you have. If it's a 5 amp station then it would trip before the breaker.
Personally I think 3.81 should be more than enough for 10 to 12 units. Did the PSX-4 trip when you added more units to the terminal or was there actually a short? My club uses PM42's and the maximum setting we currently use is 4.5 for the 2 major yards (including engine facilities). This is down from the 6 amps they were set at. The next step is to try 3 amps.
Peter
The main thing that you want, is to make sure your breakers trip before the booster or command station does. So the max setting that you may want on an 8 amp booster is 7.5 amps, if that setting is available. Test it and make sure the breaker WILL trip before the booster or command station. If not, reduce the trip point setting.
However, if you trip two breakers at the same time, will that take out the command station? You really don't want that to happen. If that would be the case, the total trip point setting of the two breakers should be less than what the command station will trip at. If there is not much chance of the two tripping at the same time, then you shouldn't really worry about it.
For your diesel engine terminal district, you may want to think about breaking that up into two parts or sub-power districts by dividing the tracks and adding another breaker.
Just as information, I don't have anything against the PSX series of breakers, but I like the NCE EB1's better. Mainly because they are single unit breakers. You can buy what you need instead of getting them in pairs, and they cost less with the same protection but without the bells and whistles. I am using them on my own home layout, and as the Electrical Foreman at our club (Digitrax system), we are using them there too and they are working well.
I hope this helps.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Thank you for the input. As additional information, the system is 5 amp, with a second 5 amp booster, and with two 5 amp power supplies.
If I understand correctly, having the breaker point at under 5 amps is preferred, as having it over 5 amps means that the system would shut down before the breakers.
Putting it all together, then I should leave it alone, or add an additional power district by dividing up the diesel terminal.
3.8 amps should be plenty for 10 to 12 locos even if all had sound. I take it they were not all moving at the same time? I had 11 HO scale locos MUed together with my 1.7 amp Power Cab system and 7 of those had sound and moving too. I would check your yard and your locos for a short or a draw. Could there be a feeder that is on the wrong rail? Are there lighting in buildings hooked to the rail power? An unseen reverse loop? Out of phase between districts? The list is long but some things to check out. My brass steamers have un-insulated front couplers and will short if hooked together.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Pete,
To answer your questions, there is no lighting, feeders are correct, no reverse loop, and the districts are in phase. The locos are all Stewart/Proto/BLIs. The "short" situation has two peculiarities:
- it happened when the power was "turned on", although the previous sessions had no outage and nothing was changed/touched between sessions.
- The one that happened today showed up when I turned on the power, after I shut it down about an hour earlier. At this startup, a main line - containing an ABBA all powered/all sound consist. I then took off an A unit and then a b unit. Upon taking off the B unit, the remaining AB powered up. So I added back the second B, and then the second A, and they powered up too!
OK that last post cleared up a bunch of things. What has happened was when the layout was powered up there was a great deal of inrush current charging up the capacitors in all those sound units all at once. I believe there is an adjustment for large inrush currents on the PSX units without changing the breaker amp settings. Our club had the same thing going on in the loco service yard. It has its own 5 amp booster but it would show a short in power up. What we did was put the roundhouse tracks on a rotary numbered switch and broke up the diesel house and ready track into blocks so they can be selected. This also dimmed down all that idling loco sound and steam engine random sounds. The coal dock, sand and fuel racks and ash dumps and loco wash are not blocked out. If a loco is parked at those facilities when the power is turned back on then they will power up. How you break up your yard is up to you. You could use on/off toggles to one rail of each yard track or break up the yard with several more PSX or even the less expensive On Guard units or even wire in an auto taillight bulb (1156) if you can not adjust the PSX unit.
Inrush current. The whole reason for the PSX line in the first palce, over the PS or Digitrax PM42. There is another option you can try, the one labeled "Weak SYstem Boost" which is supposedly only needed on lower power systems liek the Zephyr or NCE PowerCab, but since it attempts to handle the sudden current inrush without passing it along to the base system, it might work here as well. Should be no downside.
I came home from yet another week away from hoem to find my Atlas Trainmaster waiting for me, so now I have at least oen loco with each of the popular sound decoders, plus a Digitrax one I never installed in anything. I've tried with Loksound and Tsunami locos on the track and my PM42 handles it all liek a champ. We'll see now with a QSI. Plus I'm curious to see if my PR3 can program it - it handles the Tsunami just fine.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks All !
OK, to enable the "weak system boost", I need to install a jumper in the J7 block "4 to 3".
It looks like 20 awg wire will work as the jumper, with a little solder. Is that a good path to follow, or is there a better/preferred way?
Thank you!
I believe the holes are set apart to use circuit board header pins on which you then place a jumper cap, which makes it easy to turn on and off, although if you don't plan on changing this more than once, a small loop of wire jumpering the holes will work just as well. You'd pay 10x as much in shipping as you would for the smallest quantity of header pins and a couple of jumper caps and have lots of leftovers.
Hi!
I used #18 awg, 3/4 inch long, bent in a U with a small piece of wire insulation installed in the middle. All 8 fit in nice and snug, and its highly likely they won't need soldering.
To do a quick test, I powered on the layout, turned the sound on all 13 of the sound units (yikes!), and powered the layout down. I waited a minute, and then powered back on, and all the sound units kicked in. I then ran some 4 unit consists, and all was well.
The fix makes sense to me, as that initial turn on "burst" is a lot higher than once the layout is already running. I'm sure there is a more correct way of saying that, but I think you all get the point.
Once again, thanks all for contributing towards my DCC education!