DC Bus in a Loop Configuration. Problem?

[LKO Railroad]

I have not witnessed it myself but hear tell of other people that say you can see small sparks if the room lights are down. Don't know if it occurs on every model railroad or if the people witnessing it don't clean their track well or often enough. The locomotives have all wheel pickup and are quite heavy so I tend to think at least two wheels on either side are in contact with the rails at any given time. I'll soon find out for myself.

 

[LKO Railroad]

I would see how it runs without any modifications first. If you start to have issues like jittering trains or trains that won't run then we can look at implementing some of the solutions discussed.
Adam

Follow-up to let you know everything works great. I added resistance loads (20 ohm 100W) to each bus at the farthest point from the supplies. Trains run perfect with no electrical oddities. Thanks again for your help.

 

[Arouse1973]

Hey looks great nice for you to let us know how you got on.
Thanks
Adam

 

[Martaine2005]

Nice job!
A wet cloth around the glue joints would have been superb!!
JOKING!!!!
This is not about carpentry
Thanks for sharing..

Martin

 

[LKO Railroad]

Actually, it is by design. You are seeing glue fillets applied with my finger after the pieces were installed. It makes the joint much stronger. Learned from my days long ago building model rockets. Glue fillets made the fins stay on better. The camera flash really makes them show up.

 

[Martaine2005]

OK, still a great job by the way..

Martin

 

[LKO Railroad]

Hey looks great nice for you to let us know how you got on.
Thanks
Adam

Hello again Adam,
Thanks to your help my system is operating fine however, I am curious to learn more about why adding additional load to the circuit helped stabilize it. I have Googled my brains out and can't seem to find reference to dampening by adding load.

Could you explain in semi-layman terms please?

 

[Arouse1973]

Hello
Nice to see it's working ok. When a fast rising edge hits a series LC circuit it can cause ringing, this is due to the signal actually being made up of many sinewave, although it looks square. It's quite likely that the fast rising edge of the signal will contain a sinewave which matches the resonant frequency of the tuned circuit or there about. Adding the resistor quickly diminishes the energy first put in to make the magnetic field around the inductor once the signal is not present anymore, like a pulse is only on for a short amount of time. This is like spoiling the tuned circuit, very little energy stored in the capacitor is allowed to go back into the coil to try and maintain the collapsing magnetic field so the circuit stops ringing much quicker. So to put it another way, the resistor steals the energy from the circuit so it doesn't have enough to resonate.

Thanks
Adam

 

[LKO Railroad]

Hello
Nice to see it's working ok. When a fast rising edge hits a series LC circuit it can cause ringing, this is due to the signal actually being made up of many sinewave, although it looks square. It's quite likely that the fast rising edge of the signal will contain a sinewave which matches the resonant frequency of the tuned circuit or there about. Adding the resistor quickly diminishes the energy first put in to make the magnetic field around the inductor once the signal is not present anymore, like a pulse is only on for a short amount of time. This is like spoiling the tuned circuit, very little energy stored in the capacitor is allowed to go back into the coil to try and maintain the collapsing magnetic field so the circuit stops ringing much quicker. So to put it another way, the resistor steals the energy from the circuit so it doesn't have enough to resonate.

Thanks
Adam

Awesome explanation. Got it. Thank you.

 

[Arouse1973]

Glad I could help.
Adam

 

[Sunnysky]

The DCC. 2V pulses are 58us and 100us for 1 & 0.
This spectrum includes 50kHz and harmonics up to 0.5 MHz or so.
Brush motor noise covers many decades and exceeds this bandwidth but are lower amplitude than .2V if filtered when by the train when DCC is confined to this decade of signal.

It would not make much difference to use redundant track power clips at each and every location needed and would be similar to having booster power supplies, but perhaps less effective. Poor track connections are difficult to locate unless one has a mV DMM and a high power dummy load at the furthest distance from the supply., then any signifant drop in each track joint can be tested easily by its mV drop with a probe pair. Repeat for each. rail

I would prefer you use flexible welders cable to provide power and after locating bad track connections, join end of track to source power with same cable and move dummy load to middle and see improvements in track voltage.

A 3 Ohm dummy load.will draw 5A and 75W Max. If you don't have one, try a car high beam.