07-30-2010, 08:57 AM
Nice video Charlie. I'm not a passenger train fan, but I admit that your locos and cars look very good, and to see them actually rolling along was nice. Thanks for sharing that.
On the DCC: Charlie, I'm sure you know the following, but I'm throwing it out there for the benefit of any newbies who may be following along. Have you tried the "quarter test" yet? You mentioned you will put more feeders which is good. Even though the trains will run perfectly fine with minimal feeders and a relatively high resistnace, the issue is with shutting down the booster on a short circuit. Because DCC alows us to run multiple trains, the booster overcurrent protection is typically rated 5 amps or even more. Five amps is enough to melt stuff and cause fires if a short circuit occurs and we don't get it shut off.
We need all the feeders and bus wiring to keep the resistance low enough to allow the overcurrent protection to work. As an example, say we use small wire to feed a track which is quite a distance from the booster. If we have a short circuit and the overall resistance is, say, 3 ohms, with a booster voltage of, say, 13 volts, then the current flow through the short circuit will be 4.3 amps. This will not shut down the booster and the 4.3 amps will continue to flow which could melt stuff and start a fire. And that is why we need the extra feeders and bus wiring.
And, it isn't that DCC wiring is more complicated than the simplest DC system, there is just more of it. And compared to a block controlled DC system, DCC is much much more simple.
On the DCC: Charlie, I'm sure you know the following, but I'm throwing it out there for the benefit of any newbies who may be following along. Have you tried the "quarter test" yet? You mentioned you will put more feeders which is good. Even though the trains will run perfectly fine with minimal feeders and a relatively high resistnace, the issue is with shutting down the booster on a short circuit. Because DCC alows us to run multiple trains, the booster overcurrent protection is typically rated 5 amps or even more. Five amps is enough to melt stuff and cause fires if a short circuit occurs and we don't get it shut off.
We need all the feeders and bus wiring to keep the resistance low enough to allow the overcurrent protection to work. As an example, say we use small wire to feed a track which is quite a distance from the booster. If we have a short circuit and the overall resistance is, say, 3 ohms, with a booster voltage of, say, 13 volts, then the current flow through the short circuit will be 4.3 amps. This will not shut down the booster and the 4.3 amps will continue to flow which could melt stuff and start a fire. And that is why we need the extra feeders and bus wiring.
And, it isn't that DCC wiring is more complicated than the simplest DC system, there is just more of it. And compared to a block controlled DC system, DCC is much much more simple.
Three Foot Rule In Effect At All Times