I recently purchased a PSX-4, and I am about to divide my layout into four power districts, the main lines, and three multi-track loco storage facilities.
I tested the PSX-4 on the work bench with four separate sections of flex track. Did the quarter test on each section and the circuit breaker for that section worked as expected.
So, last night, without gapping and isolating the three multi-track loco storage facilities into separate power districts, I wired the first of the four circuit breakers from my command station and brought my layout bus wires into the output side of that first circuit breaker.
Turned on the power and nothing except for flashing headlights on several locos.
Then, it dawned on me. My PSX-4 breakers are set to factory default at 3.81 amps. My NCE DCC system is 5 amp. So, apparently, the PSX circuit breaker was shutting off the system with the lower amperage setting and then trying to reset itself, causing the loco headlights to flash on and off.
Without separate power disrtricts, the PSX is controlling the entire layout.
But, what confuses me is that my RRampMeter is not showing more than 2 amps current draw when I bypass the PSX circuit breaker. So, what is going on here?
Rich
Alton Junction
Any of those sound locos? Enable the "weak system boost" option, the PSX is seeing the inrush as a short. That option will help.
--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 Any of those sound locos? Enable the "weak system boost" option, the PSX is seeing the inrush as a short. That option will help. --Randy
Randy, in the future, I would appreciate a more prompt reply.
Seriously, though, thanks for the quick reply.
Yes, there are lots of locos on the layout and lots of sound locos. That's the main reason why I want the separate power districts, one for the steam engine servicing facility (roundhouse, turntable, coaling tower, back shop), one for the diesel servicing facility (sand towers and car shop), and one for the downtown passenger station and coach yard.
I suspected the current in-rush as the culprit. Yikes, I may be closer to the 5 amp booster limit than I first thought.
I wonder why the RRampMeter doesn't reflect these total amps?
I do not believe the RRamp Meter was designed as an averaging meter and the output needs to be steady to get a reading on the digital screen
An anloge meter can record quick varations in reading - as you can see the needle move - but you are not going to be able to get an accurate with those either.
Some digital meters have a MAX hold setting which will read those spike varations and you can then read them back - I have one of those types of Digital Readout meters!
BOB H - Clarion, PA
Thanks, Bob, for that info. I kind of suspected that intuitively, but your comments confirm that intuition.
I wish that the PSX gave me more flexibility to experiment with the trip current. After the 3.81 setting, the next setting is 5.08 amps, so I cannot determine the exact extent of that in-rush of current. Is it 3.9 amps, 4.1, 4.5 amps?
Inquiring minds want to know.
Well, that's sort of why they added that "weak system boost" option. So you cna leave the absolute trip current to a reasonable 3.8 amps, yet still handle a momentary inrush if there are sound locos in the section.
You cna probably assume your inrush peak is not much over 5 amps, or else your system would have tripped when it was hooked directly to the rails. Unless that WAS a problem before. The inrush can't be say 12 amps when the power supply can only supply 5 amps, and maybe a tiny bit more, but not over 2x the steady rating.
Rapid changes are one area where analog meters still have their place. Most digital meters react too slowly and so don;t catch transient events like a quick spike or surge. For an extreme exampel fo the same thing happening, consider the voltage readout. It shows you a nice steady voltage. Now look at the track power using an oscilloscope. The DCC power is anythign BUT a nice steady voltage. It's constantly dropping to 0 volts even. Just like the AC voltage in your wall outlet. Or why a meter set on DC volts generally shows 0 volts on DCC - it's reversing polarity so fast the meter can;t display those swings so it can only show the average, which is nominally 0. Use a center 0 DC analog voltmeter on DCC track and you'd see the needle vibrating around the 0 mark, not steady, as it vainly tries to follow the voltage swings which are happenign too fast for the needle and coil to avtually move.
I don;t think you can change the trip speed on NCE boosters, on Digitrax you can set them to one of 4 settings. Ideally you want an autoreverser to be the fastest acting device, then regular breakers feeding that to be the next slowest, and finally the booster to be the slowest of all, this way when a train trips an autoreverser, it reacts and fixes the short before the breaker or booster can shut down, and if tehre is a short in a power district, the breaker will react and cut power before the booster does.
Randy,
I haven't been down to the layout yet today to try the Weak System Boost option which would be the J7 jumper.
I had considered using the J6 jumper option to increase the trip current to 6.35 amps on the circuit breaker. But, I changed my mind after I read your reply about keeping the trip current lower on the circuit breaker than on the booster (5 amps). I don't know of any way to change the trip speed on the NCE booster, by the way.
After reading your reply, I have an additional concern about my layout because I have 5 auto-reversers (all Digitrax AR-1s) on it. Three are on the main lines which will be one power district, and one is in the engine servicing facility which will be a separate power district. But, the fifth one is in what will become a separate power district, the downtown passenger station and coach yard, and it is one big reversing section.
Thoughts?
It should be fine having the AR-1 downstream of the PSX. As long as the AR-1 is adjusted correctly, it should flip before the PSX cuts out, but if a real short occurs, the PSX will still open up and cut power.
I just set the J7 jumper to enable the Weak System Boost option and that worked. So far, so good.
But, then I did the quarter test just to be certain that all was working right.
However, the quarter test failed to trip the PSX breaker or to shut down the booster. Now what?
More feeders. And/or thicker wire for the bus.
And clean the track. Maybe the quarter, too, if it's heavily tarnished.
rrinker More feeders. And/or thicker wire for the bus. And clean the track. Maybe the quarter, too, if it's heavily tarnished. --Randy
The bus wire is 14 gauge solid copper.
I will try a different quarter, but it is the same one that I used to test the PSX-4 on four different pieces of flex track on the work bench.
I have a feeling that I will need to set up the first of the three non-mainline power districts to test this setup properly.
Rich,
Doesn't work very well at all, with those wood quarters.
Frank
I have two heavy steel points rail shaping blocks that I purchased from Fast Tracks in 2006. I don't use a quarter because I don't think they are heavy enough, and their stamped features on their faces don't always allow good contact. On the other hand, these blocks I'm talking about, when placed across both rails, are a very positive bridge between them. If I need to test for voltage strength and shorts detection, that system is foolproof for me.
Hmmm, I am momentarily stymied.
I set up one of the non-mainline power districts, strung the bus wires, gapped the rails and re-wired the feeders to the new bus wires.
So, at that point, there were two power districts, (1) the diesel servicing facility and (2) everything else on the layout.
When I powered up, both power districts were indicating shorts. My RRampMeter would alternate between zero amps and about 2.25 amps, indicating that the system was trying to reset itself and then shorting out again. Tried the Weak System Boost Option to no avail.
Then, I disconnected the bus wires for the diesel servicing facility power district, and everything worked fine except, of course, the disconnected power district. The rest of the layout was operating through one of the other four PSX circuit breakers without a problem.
So, the section of track that I call the "diesel servicing facility seems to be a problem. There are 16 diesels sitting on those tracks, some with sound, some without sound. None of them are programmed to produce sound or lights until I start them moving. I just had a thought. I will reconnect the bus wires to this power district and remove locos one at a time to see if I can eliminate the short.
Awww geez,
Like George Washington, I cannot tell a lie.
I committed a newbie error. Three pairs of feeders were crossed.
Back about 4 years ago, I added the diesel servicing facility to my layout. At the time, the three tracks leading into the car shop were installed without feeders, but I soon realized that feeders would be helpful. At the time, I crossed the feeders when I wired them and, in a careless moment, I corrected the resulting short by swapping the feeders on the bus wires. Totally forgot about this until yesterday when I disconnected all of the feeders in this section.
I am totally embarrassed but, what the heck, I have done worse. Everything works now, no need for the Weak System Boost option. I have decided to ban myself from the hobby indefinitely...............until tomorrow.
Really sounds like inrush is getting you, despite the "weak system boost". Despite all the hype, even the PSX breakers have a few issues with this. At least on the Digitrax list, you get constant messages saying to ditch the 'useless' PM42 and switch to teh 'far superior' PSX, but you are not the only one seeing that the PSX isn't as smart as they claim it is and will still have issue with sound decoder inrush. The inrush is there, even if the decoder is configured to not make noise until selected. I'll bet as you take locos off you will hit a number that works fine, and adding one more sound loco will cause it to not reset. You can try a higher amp setting - the PSX will still react quicker than the command station, and the higher amp setting on the PSX may allow it to restart this district loaded with locos.
Worst case - you may have to make 2 power districts out of the terminal, so that there are never more than whatever you discover the limit to be of locos on any on PSX section. Something else people have done, both with PM42's and PSXs, is to jump around the breaker with an 1156 taillight bulb. This seems to allow the inrush to be handled without trippign the breaker but if there's a real short which exceeds the 2.1 amps of the light bulb, the breaker still trips. I'm not a huge fan of that though.
Not suggesting getting a PM42, you really need a Digitrax ssystem to configure them, so they aren;t suited for use with other brands. I don;t have as many sound locos as some, but I ut all of them I have, 5, plus a couple other non-sound locos in one power district and shorted the track. My PM42 recovered just fine. Others have claime as fes as 2 sound locos cause the PM42 to not reset - I say, insufficient wiring. Of course the majority of my soudn locos are Loksoumd, which never had an inrush issue, nor any issue with programming without boosters and add-ons. And then again, I've been able to read and program any brand decoder with my PR3 witht he standard PS14 power supply, no PTB-100 or any othe rnonsense. Others say you need to get a laptop power supply witha higher voltage for it to work with sound decoders.
Randy, I just wrote my reply as you were posting yours.
I finally found my error by bypassing the circuit breakers and connecting the newly created power district directly to my command station.
When I did that, I had a dead short - - - - with all the locos off the tracks - - - so I knew instantly that I had crossed feeder wires. When you read my prior reply, you can see how I was fooled by my own mistake four years ago.
My bad.
Honest Abe.
Was it George the one who had wooden dentures?
Oops. SO you have 3 sets of feeders you soldered to the wrong rails, so they actually have to be hooked up what seems to be incorrectly in order to actually be correct? Even after all this time, I'm not so sure I wouldn't just unsolder them from the rails and do it over the right way so next time you change wiring around you don't run into thsi same problem again. At the very least - dor these wires, wrapa flag of maskign tape around them and write on it a short explanation of why they are wired the way they are using a permanent marker, so at least it's documented. This is the sort of thing that also should be ina wiring manual, however for what you are doing it might not be something you'd go dig through a book to verify. Having the documentation on site attached to the affected wires is probably the best option short of doing it over the right way and fixing it for good.
Consistency and good documentation are the keys to having all this electrical mumbo-jumbo workign right. Even though my (now being ripped out) layout was pretty simple, single track around the room so it was obvious which rail went to which feeder, I did attach wire labels (those number/letter sheets you can get at the home store) and kept a document recording which each number set represented. New layotu is going to end up much more complex (notwithstanding that I am goign to wire it from the start for signalling and detection - that means detection sub-districts within each pwoer district) so the documentation will be even more important.
rrinker Oops. SO you have 3 sets of feeders you soldered to the wrong rails, so they actually have to be hooked up what seems to be incorrectly in order to actually be correct?
Oops. SO you have 3 sets of feeders you soldered to the wrong rails, so they actually have to be hooked up what seems to be incorrectly in order to actually be correct?
Yep.
rrinker Even after all this time, I'm not so sure I wouldn't just unsolder them from the rails and do it over the right way so next time you change wiring around you don't run into thsi same problem again. At the very least - dor these wires, wrapa flag of maskign tape around them and write on it a short explanation of why they are wired the way they are using a permanent marker, so at least it's documented.
Even after all this time, I'm not so sure I wouldn't just unsolder them from the rails and do it over the right way so next time you change wiring around you don't run into thsi same problem again. At the very least - dor these wires, wrapa flag of maskign tape around them and write on it a short explanation of why they are wired the way they are using a permanent marker, so at least it's documented.
Thanks, Randy, I took your advice and tagged those swapped wires.
I just completed the third power district, the steam engine servicing facility. So, now, I only have one power district left to do - - - the passenger station / coach yard which is one big reversing section.