Seems the original thread “Can’t Understand system short” was getting too long so I was asked to start a new one.
The last thread left off with NCE Receiveing 3 failed circuit breakers and telling me that it will be at least 6 weeks before they can look at them.
Gary
I kinda liked the old thread.
Rich
Alton Junction
Rich, the old thread was getting to be tooooooooooo long. I asked Gary to start a new one.
Bear "It's all about having fun."
bearman Rich, the old thread was getting to be tooooooooooo long. I asked Gary to start a new one.
Rich, we can always recap if necessary. Sine what? It's Greek to me.
I'll meet you back here in May when there is something new we can argue about.
Henry
COB Potomac & Northern
Shenandoah Valley
Henry, you are as cynical as I am. but the truth is, I really want to know what the problem was.
True, but we chewed it over 9 ways to Sunday. As Sherlock Holmes said I cannot reason without more facts.
I sent a fried decoder back to NCE and it took so long, I figured it got lost in the mail, May is probably the minimum wait.
Well, if it really is going to be May before Gary hears anything from NCE, that is a long time to wait to get the layout up and running with those three power districts.
From all the testing and troubleshooting that has been conducted including continuity and voltage tests, along with power district testing with a known good EB1, there is little doubt that the problem is anything but three messed up EB1s.
Gary ought to consider purchasing three new circuit breakers, either EB1s or PSX units, to get that layout up and running. If it were me, I would do it now and determine later whether NCE can offer any help in the way of new or repaired EB1s.
Too long? It had just passed that screwy point where you get pages like -1 and -2.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
richhotrain Well, if it really is going to be May before Gary hears anything from NCE, that is a long time to wait to get the layout up and running with those three power districts. From all the testing and troubleshooting that has been conducted including continuity and voltage tests, along with power district testing with a known good EB1, there is little doubt that the problem is anything but three messed up EB1s. Gary ought to consider purchasing three new circuit breakers, either EB1s or PSX units, to get that layout up and running. If it were me, I would do it now and determine later whether NCE can offer any help in the way of new or repaired EB1s. Rich
My thoughts exactly!
And I think i’m going with a PSX4 and loose the terminal block.
Gary, did you get a chance to read my post, the last one in thread #1?
Mike.
My You Tube
DONE $144w/shipping
You are sure the wiring is bulletproof? Mike's last comment on the other thread referred to how you wired your layout for DC before you converted to DCC.
bearman You are sure the wiring is bulletproof?
You are sure the wiring is bulletproof?
The series of continuity tests and voltage tests that Gary performed seem to have confirmed that the wiring is correct and that there are no cross-wired feeders to other power district buses.
But, even if there are one or more cross-wired feeders, that should not damage the new PSX circuit breakers. The new PSX units should be wired and tested one at a time, leaving each PSX connected as the next PSX is wired and tested.
In this way, if there is any faulty wiring, it can be detected in a logical manner.
Rich, I will defer to your opinion on the wiring. But, and I suspect we will never know the answer, why did the EB1's get fried in the first place? Only that they were fried.
bearman Rich, I will defer to your opinion on the wiring. But, and I suspect we will never know the answer, why did the EB1's get fried in the first place? Only that they were fried.
That said, I have a hard time imagining a way in which improperly wired feeders can damage a circuit breaker. Maybe Randy can offer possible scenarios.
If, indeed, one or more of the EB1s are fried, I think that the most likely explanations are either a power surge caused by lightning or else an improperly wired EB1.
Lighting doesn't seem entirely plausible since the route of the power surge would be through the command station where the booster is housed. So, if a power surge caused by lightning fried the EB1s, you would think that it also would adversely affect the booster.
So, unfortunately, I think that something Gary did probably caused the failures. He could have wired the EB1s backward, that would surely damage the circuit breaker(s).
Another thing I wonder about is the use of a washer to do the quarter test. That large washer can tempt the user to take advantage of the larger surface to press down hard on the washer to generate the short.
Is it possible to press down too hard and too long to cause excessive and prolonged current to blow the circuit breaker? Randy?
Then, the only thing to do is sit and wait for the PSX4 to be wired up, and on the report from NCE. Washer, quarter, screwdriver, they should short out and the CB should trip and shut down the power. I mean, how long is long?
mbinsewi Gary, did you get a chance to read my post, the last one in thread #1? Mike.
Hi Mike, Must have missed it.
Assume you mean this?
Gary, I have a question that I have been pondering over when this thread was starting getting hot and heavy into the "what happened?" phase.
I read, a few pages back, that you originally wired this layout for DC. If that's true, would you mind explaining how you did it? Did you devide it into "blocks"?, and if you did, did you only gap one rail to seperate the blocks? By the way, if you did it this way, the rail without the gaps is the "common rail" you asked about.
And if you did all of this, what did you do to the wiring when you switched over to DCC?
I'm just really curious about all of this. I'll be waiting along with the rest of you for the info from NCE.
Yes it was a DC Layout. No both rails were gapped. All the wiring was ripped out for the tracks. Wiring for lighting was left. That caused a problem with one old feeder (telephone wire same as lighting) that was under ballast and connected to one rail near a tunnel portal. After several posts i found it and removed it.
DCC is 12ga busses (3) and 18ga feeders with each bus feeding from a circuit breaker.
bearman Then, the only thing to do is sit and wait for the PSX4 to be wired up, and on the report from NCE. Washer, quarter, screwdriver, they should short out and the CB should trip and shut down the power. I mean, how long is long?
That is a question for Randy or one of the other electrical gurus. Can a constant dead short eventually damage a DCC circuit breaker?
Rich, for me that last question of yours is rhetorical.
bearman Rich, for me that last question of yours is rhetorical.
There were some times when I did push down on the washer because it was sparking. But no induced short lasted more than a few seconds.
Something happened with the EB’s because when initially installed they all worked and shut down only the associated district when short tested.
I’m No electrical engineer but the wiring of the EB1’s is not rocket science.
It's rhetorical because I am clueless as to the answer. And Gary, it sounds like everything is aok with your wiring. When is the PSX4 supposed to arrive?
bearman It's rhetorical because I am clueless as to the answer. And Gary, it sounds like everything is aok with your wiring. When is the PSX4 supposed to arrive?
Order placed yesterday. I guess sometime next week.
gdelmoro I’m No electrical engineer but the wiring of the EB1’s is not rocket science.
On the PSX, the input side has four ports for two sets of wires whereas the output side has only two ports for the bus wires for that particular power district.
So, the operator has to be careful not to connect the bus wires to the input side of the circuit breaker.
Page 5 of the PSX Manual has a really great picture of how to wire the PSX4. But with three power districts only three of the units will have to be wired and the two PSX-AR shown there can likewise be ignored.
richhotrain bearman Then, the only thing to do is sit and wait for the PSX4 to be wired up, and on the report from NCE. Washer, quarter, screwdriver, they should short out and the CB should trip and shut down the power. I mean, how long is long? How long is long? Can it be too long? Dunno. That is a question for Randy or one of the other electrical gurus. Can a constant dead short eventually damage a DCC circuit breaker? Rich
How long is long? Can it be too long? Dunno.
Depends on how much marketing had to do with the design. Really. If the compnents are just squaking by in terms of current capacity and so forth, keeping a short in place and walking away for an hour to eat dinner is probably a bad idea. Probably a bad idea anyway. If the components are robust enough, say switching a peak of 5 amps through a transistor designed to handle 10 amps, they really should last forever, whether you get one short a day or one short a month.
As I mentioned though, just a guess since there's no schematic, but it could be that if power is fed back in the inputs, it could be applying enough voltage or current difference across a different part of the circuit that isn't meant to handle those sort of loads and never would under normal circumstances. You can't reverse protect DCC circuits like you can a DC circuit, to prevent hooking up the power the wrong way, because with DCC the current needs to flow in both directions. On DC circuits it's common to have a diode or similar component in the power leads, so if you accidently hook the + to the - and vice-versa, no current flows and nothing happens.
So if in the past there was a crossed feeder and one of the EB-1s got power fed in the outout, even if that crossed feeder has long been corrected, the damage may have already been done. If shorts are infrequent, it could run for months damaged and you'd never know it, since they were passing power to the track just fine - they just weren't cutting it off when a short occurred.
Thanks Gary for taking the time to answer my question.
It was just a question in my mind, and if you did the common wire method for DC, could something be wrong when you changed things.
Obviously you did it right, and I guess all the tests that you and Rich did would have found something.
rrinker So if in the past there was a crossed feeder and one of the EB-1s got power fed in the outout, even if that crossed feeder has long been corrected, the damage may have already been done.
So if in the past there was a crossed feeder and one of the EB-1s got power fed in the outout, even if that crossed feeder has long been corrected, the damage may have already been done.
As I understand the DCC circuit breaker, power is fed into the input side of the circuit breaker, either directly from the booster or through daisy chaining of multiple circuit breakers.
That power input is fed to the respective power district through the output side of the circuit breaker. Excessive current caused by a short enters the circuit breaker through the output side of the circuit breaker, and if the resulting amps exceed the trip current setting, the circuit breaker will trip cutting off power to that power district. If the circuit breaker fails, that excessive current will reach the booster which will shut down the entire layout.
In the case of a crossed feeder, what would happen in the event of a short? Would the excessive current trip both circuit breakers, the circuit breaker for the power district where the short occurred and the circuit breaker affected by another bus where the crossed feeder was connected? If so, how would that damage either or both affected circuit breakers?
I am trying to understand how crossed feeders can damage one or more circuit breakers, maybe even all three circuit breakers in one catastrophic event.