LION has tried the LIGHT TRICK... and is pleased with it. Him will incorporate it on the layout of him, but him will need about four lights in parallel for the amount of current him consumes on the layout of him.
LION has a 10.2 volt x 12 AMP regulated power supply with current to the tracks at all times, but him has not DCC. Problem is in the tracks. LION has embedded resistors to slow the trains down at the stations (and a gap to stop the train). If a train derails between the resistors it will draw enough current to burn the resistors, but no where near enough to trip the power supply's internal protections. Power supplay says : "Ah, you want 5 amps, ok, I got that for you." and simply does not suht down for such a short.
LIGHTS coming on, on the other hand, tell me that there is a problem and to go look for it.
As a matter of fact, a smaller fuse would do the same thing, but it might not wake up the sleeping LION to the fact that their is an issue out there. LIONS frequently run trains without even watching the layout, him is at the work bench with some other project.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
maxmanI don't like any of the bulb options. In my opinion they are just an old fashioned method of accomplishing something that one of the new circuit breakers does better. Plus, I don't think they "protect" anything. You still have current flowing that is potentially damaging, not to the Powercab, but to things on the railroad.
Except the light bulb it significantly cheaper and does limit the current. It's the current that does the damage usually. Not the fact it's moving through a part, but there's too much.It's an acceptable answer and works well when bridging DC-DCC sections
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
"I'm with Maxman. The DCC Specialties OG-CB is perfect for the PowerCab. Costs only $25 at either Tony's Train Exchange or Litchfield Station, both very reputable dealers."
Erik Fiske, Tony's Train Exchange
Erik Fiske
I couldn't fix your brakes, so I made your horn louder
maxman I don't like any of the bulb options. In my opinion they are just an old fashioned method of accomplishing something that one of the new circuit breakers does better. Plus, I don't think they "protect" anything. You still have current flowing that is potentially damaging, not to the Powercab, but to things on the railroad.
I don't like any of the bulb options. In my opinion they are just an old fashioned method of accomplishing something that one of the new circuit breakers does better.
Plus, I don't think they "protect" anything. You still have current flowing that is potentially damaging, not to the Powercab, but to things on the railroad.
Rich
Alton Junction
maxman gregc I'll add a switch to place the bulb in the track circuit when troubleshooting a short Although someone else mentioned doing this, I don't think I understand how putting the bulb in the circuit helps troubleshoot anything. If there is no short, the bulb does not get put into the circuit. And if there is a short, I think that would be recognized before putting the bulb in the circuit. From what I've seen of shorts that occur during operation, they are mostly caused by some unwanted interface between the train and the rails. So that immediately gives a starting point. I don't think I see any advantage to search for such shorts with current still flowing, other than looking for something that has become extremely hot to the touch. Maybe there is something I'm missing.
gregc I'll add a switch to place the bulb in the track circuit when troubleshooting a short
Although someone else mentioned doing this, I don't think I understand how putting the bulb in the circuit helps troubleshoot anything. If there is no short, the bulb does not get put into the circuit. And if there is a short, I think that would be recognized before putting the bulb in the circuit.
From what I've seen of shorts that occur during operation, they are mostly caused by some unwanted interface between the train and the rails. So that immediately gives a starting point. I don't think I see any advantage to search for such shorts with current still flowing, other than looking for something that has become extremely hot to the touch.
Maybe there is something I'm missing.
Well, on a larger layout, with a 5 amp system, or maybe even multiple booster, you can break the layout down into even more sections with a light bulb on each. This can serve two putposes - it will tell you exactly which section a train has shorted in, which sure, is very simply when you're the only one running and only one train is running, but not so much with a dozen operators having 8 trains on the move simultaneously, and second, since the current allowed by the light bulb is less than the booster output, only the shorted train stops and gets a lit up light bulb, other trains in different sections keep right on going.
Dick Bronson at RR-CirKits published a slightly more complex alternative to the simple light bulb, using a PTC resistor to controla dual filament bulb. It starts out allowing the 2.1 amps of the one filament to keep flowing, but then switches to the .4 amps of the smaller filament. Still not as good as just completely cutting the power, but .4 amps keeps the current low enough to not melt plastic trucks or weld rail. This is still super cheap - the PTC resistors are less than 50 cents each, so the bulb is still the more expensive part. Not really suitable for a lower power system like a PowerCab, it will take too long to heat up the resistor and get it to flip, plus the larger filament in the bulb is 2.1 amps, which means the PowerCab would trip first anyway.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
maxmanAlthough someone else mentioned doing this, I don't think I understand how putting the bulb in the circuit helps troubleshoot anything.
I had a problem where a wheel shorted between the frog points and stock rails (I understand about DCC compatible turnouts). PowerCab would shut down and take several seconds to apply power to the track when I tried to find the problem, which made it difficult to find the problem. I probably used a voltmeter to find the problem.
I think it's another tool that can be helpful and one I don't have to hold to indicate when the problem occurs. (I'll find out).
On one perplexing project at work, someone suggested removing the fuse and look for the component that smokes. It's not always easy.
greg - Philadelphia & Reading / Reading
gregcI'll add a switch to place the bulb in the track circuit when troubleshooting a short
I should have tried this before I posted something.
maxmanIn addition, there is still current going through the bulb even though there may not be enough to light the filament. So as you add more locos, there is more current required, and the more current required starts to light the filament. So some of the current needed to operate the locos gets robbed by the lighted filament.
When I did, and tried operating a locomotive, the bulb started glowing every time the locomotive started drawing current which caused the voltage across the bulb to increase, the voltage across the track to drop, until the locomotive slowed and the cycle repeated.
maxmanPlus, I don't think they "protect" anything. You still have current flowing that is potentially damaging, not to the Powercab, but to things on the railroad.
when designing a circuit that may short, I'm usually concerned with protecting devices up stream of the short that the current passes through. This is normally the power supply but can also be switching devices, not the mechanism causing the short. If it isn't simply a metal short across the rails, it can either handle the current or is already damaged.
One way to provide protection is to simply limit the current by having a simple feedback mechanism the reduces the voltage. This is how many high quality (HP) power supplies provide protection and how I had hoped the bulbs would work.
I'll add a switch to place the bulb in the track circuit when troubleshooting a short
thanks for all the info
I'm with Maxman. The DCC Specialties OG-CB is perfect for the PowerCab. Costs only $25 at either Tony's Train Exchange or Litchfield Station, both very reputable dealers.
My problemw ith light bulbs is, they aren't cutting anything off. Whatever current flows through the light bulbs, flows through your 'short'. For 5 amp and up systems, the commonly used bulbs allow about 2 -2 1/2 amps to flow. That's 30+ watts, which can still generate significant heat. For the PowerCab you need lower current bulbs, or the PowerCab will just trip and there will be no benefit - NCE has the CB6 which has 6 1 amp bulbs in it which would work for this.
In addition, there is still current going through the bulb even though there may not be enough to light the filament. So as you add more locos, there is more current required, and the more current required starts to light the filament. So some of the current needed to operate the locos gets robbed by the lighted filament.
Just my opinion.
i have a small layout with an NCE PowerCab which works great. But it's time consuming to locate a short when the PowerCab takes several seconds to reboot (?) after detecting a short.
I tried putting a 3021 dome light bulb in between the PowerCab and track both to indicate the short and limit the current to avoid the PowerCab reboot. A short causes the bulb to light up brightly and the PowerCab doesn't reboot. Seems like relatively in expensive ($7.50) automative short circuit protection.
Can anyone think of a reason this would damage the PowerCab?