Hello all! I have a question about short protection on my DCC layout. Watching this video on how he does it, I do want to apply similar to my layout, with a slight change though. Instead of strapping the bulbs under the layout, I would like to wire a LED direct to the control panel. Basically, if there's a short on one of the sections, the LED lights up to the corresponding section of track. I'd like to know which resistor (+ LED) will replace the light bulb he's using in the video so the LED does not just pop with the load hits: Bulb in video: 12.8v / 26.88w thanks.
I'd think if you add a resistor with a LED you aren't accomplishing the same thing as the bulb like he is using but maybe I'm not looking at it from the right angle. The LED will blow on more than 30 ma or so. If you ran the track power through the resistor and LED it couldn't ever exceed that or it would blow. Your engines aren't going to run on 30 ma. How many track sections (power districts) are you interested in protecting? I considered the bulb idea myself but felt better spending $40 per power district on a real circuit breaker that is designed for the job. It cuts power to both rails can be set to trip at 2 or 4 amps, trips in an instant, works with boosters up to 10 amps and is easy to wire a remote LED to. Considering the cost of locos it could easily pay for itself if it protected one that would of otherwise died. Sumner
Hi, I am thinking 6 districts in my layout. Am I going overboard with 6? or less will suffice? I am running NCE Powercab and plan on 3 engines running at the same time (maybe a 4th in the switchyard). thanks
The bulbs are a fun old skool solution; I had one on an SCR throttle I built in the '70s. You're right @Sumner that an LED with a resistor won't substitute. The bulb's filament is the key. It has almost no resistance, so it flows current normally when there's no short. The bulb remains dark. When a short happens, the filament's resistance rises and the bulb illuminates. I'm not an EE, but I think this is what I remember. It'd be a whacky solution, but fibre optic cable could be run from the bulbs to the control panel.
fiber optic good idea. i never thought about that. this could be used for one bulb then fiber optics to your buildings ect all with one bulb. Hardcoaler is exactly right about the bulb thingy...
Not a bad idea. If you have sound locos or thinking of getting them consider places you might park them and maybe be able to turn those places off/on. They are always consuming a small amount of power and also some can start and run whenever you power the track up and you might not want to have to go and turn them off (the sound). Park them and turn that track section off. Back to the bulbs. They are not a circuit breaker but a current limiter in case of a short. So if you have a short depending on the bulb you use they will probably limit the current running through the short to around 2 amps. Personally if there is a short I'd like to see the current shut off. The bulb might protect the PowerCab but they recommend a Eb1 (v1.1) circuit breaker that cost $30+ ( https://ncedcc.zendesk.com/hc/en-us/articles/201479815-Step-1-The-Power-Cab ). Wish you would of asked this question a couple years ago as it might of saved me a couple hundred dollars. I went overboard on boosters and circuit breakers thinking through your situation and mine. I have a large (physical size) layout but I'm a single operator and probably would never have more that two others operating at the same time. Maybe you are in this situation also. If my layout was a club layout with lots of operators or a home one in the same situation what I have now would be great as shorts on the layout would be confined to small areas and everyone else would continue to operate. But for me and maybe you and others if there is a short and it takes a few minutes to sort it out and everything stops is that really a big deal and the need to spend a lot more to avoid a short stoppage for the single or maybe a couple other operators? Your decision. I'd consider doing what Duncan of Tam Valley (owner and designer of their products) did using his products but you could use similar products from other manufactures. He has a large layout in his house that goes from room to room. He runs it off of a single PowerCab. A limitation to that is the 2 amp output and no circuit breaker. To deal with that the PowerCab becomes the command station only (What I do with my DCC-EX command station). It is the provider of the DCC signal only not the current that the locos draw. You can connect the PowerCab to a booster for the power. A booster like his and others (check their specs) provides the power but is also a circuit breaker. His provides 3 amps continuous and 5 amps peak. So now you have more power and circuit protection. If you end up needing more power you can add more boosters. You also need a power supply. You can get the booster for about $48 and power supply for about $16 or less. So for about $35 more than the circuit breaker for a PowerCab you have a booster and circuit breaker. You can check other manufactures products for a similar solution. Again the above is cheaper than a single loco and you have a true circuit breaker not a current limiter as you would have with a bulb. My suggestion that you might want to consider is the following. Get the booster/circuit breaker. Use your PowerCab and connect its output to the booster. Connect the 6 blocks to the booster's output with toggle switches. If you have a short turn the 6 switches off. Then back on one at a time until you see which block is causing the short. Now go to that block and resolve the short. Turn the rest of the block switches on and go back to running trains. Simple, fast, more power/current and good protection for the PowerCab, locos and anything else connected to the track. If down the road you need more power add another booster and maybe put 3 blocks on the first one and the other 3 blocks on the additional booster. I could of done this and probably got by with two boosters vs the four I have. I also added 2 circuit breakers to each booster to get 8 power districts. Not so much for the power but to make it easier to identify where a short was (layout is 24' x 6' with a divider down the middle). I could of gone with 2 boosters and 8 toggle switches and probably been just fine and accomplished the same thing. Sumner
I like your suggestion, buy the booster & breaker and wire all through there. I think that makes the most sense for the setup I have. Still section it into 6 power districts, so a short is easily found. Thanks!
I used the lights in the past, but prefer the PSXX with the sonalert on it. It's quite annoying, but effective. You will stop running up against thrown turnouts after a few triggers. The PSXX are the new version of the PSX and can be adjusted through CV's. If you are a single operator and may only have two trains running at once it may not be worth the cost to have districts. Narrowing down shorts is a matter of knowing where the trains were when one caused it.
