Thanks Greg. We are back to having me excited. This maybe a dumb question but I am an electrical idiot. How easy is it to get a 110ac to 48v DC inverter. I was going to use a 12v garden light system. How would I achieve 48v. Is there some normal converter? Would you carry the 48v from the source over the 14/2 same as using it for a 12v DC bus.
The DC to DC step down is easy and understand that part no problem.
Devon Sinsley said:
When I saw this thread I got excited then Greg ruined it.
Not uncommon Devon …apparently that same problem used to happened on the other train sites that used too exist. However as I write this I’m badgering , being unfriendly and the attack dog as it’s called these days.
Devon Sinsley said:
Thanks Greg. We are back to having me excited. This maybe a dumb question but I am an electrical idiot. How easy is it to get a 110ac to 48v DC inverter. I was going to use a 12v garden light system. How would I achieve 48v. Is there some normal converter? Would you carry the 48v from the source over the 14/2 same as using it for a 12v DC bus.
The DC to DC step down is easy and understand that part no problem.
https://www.trcelectronics.com/48-volt-dc-power-supplies
I “guess” this is what he is suggesting Devon ?
Just a question about the size of the layout and the number of LEDs that are being used.
Guessing that an indoor layout would not be that large than in size then perhaps consider a 12 or 24V DC ring main for lighting.
Ring main means both ends of the +ve and the -ve are connected to the output of the power source forming a ring.
Then the LEDs will be across the +ve and -ve lines the number which will form the load, the same voltage will be present at all points on the line.
If larger items need to be run then consider higher voltages, higher voltages will mean smaller diameter wire.
Personally I am planning to run only LEDs on my new layout so I will be able to get away with lower voltages and smaller diameter wire and a ring main.
Devon,
Think of electricity as irrigation or your garden hose;
Voltage (V)= pressure (PSI)
Current (I) = water flow ie amount of water flowing onto the ground per minute
Load = number of things on the system eg sprinklers delivering an amount of water per minute, the extremes are; no end to the hose = a short circuit (water pouring everywhere, a blocked hose = open circuit (no water at the end of the hose).
Switches = taps/faucets or water diverting devices.
This is an analogy I used when teaching my apprentices over the years, to help them get their head around the magic of electricity as they could all relate to the garden hose connected to a tap/faucet with a trigger nozzle.
I understand doing the ring thing to reduce voltage drop along the line. But why not several rings, or circuits. That way the load on each circuit can be kept low and the wire can be kept thin. Then one could model a small power substation, where all the diverging lines come together. Rural substations can be as small as a small house.
So, start with a 48v supply, you can probably find a transformer, AC or DC does not matter, but I’m going to recommend a bridge rectifier and a cap to produce DC, you will see why. This is easily available and I can help you shop.
I picked the voltage, because this is about the limit for outdoor voltages by code, that don’t need special insulation, grounding, etc, it still qualifies as a “low voltage” circuit.
So, the idea here is the highest safe voltage on the pole wires, this allows you to use the finest wire. You should be able to approach prototype wire sizes.
Now, run the wires into the buildings like you see in real life, small insulators on the roof, etc.
Here is the key to keeping it cheap and simple: once in the building, a small DC to DC inverter/regulator (this is why I specified putting DC on the poles). These are cheap, small, and adjustable. You can set the output voltage at around 3 volts and you won’t need any energy-wasting resistors, just connect your LEDs to the output. Simple, cheap.
Here’s 6 of them for $10.75 and you could run up to 15 LEDs from just one… you can indeed find them cheaper direct from China if you wait a month and a half.
I’d be happy to work with you on this project.
Greg
David Maynard said:
I understand doing the ring thing to reduce voltage drop along the line. But why not several rings, or circuits. That way the load on each circuit can be kept low and the wire can be kept thin. Then one could model a small power substation, where all the diverging lines come together. Rural substations can be as small as a small house.
Valid query …Greg ??
Yes, of course the fewer loads on the line, i.e. splitting up, would reduce loads.
But how far do you want to go? If you want to follow the prototype, many homes come off the intermediate lines, the 3 wire, approximately 5,000 volt lines on telephone poles.
In any case, my suggestion is easy to do, inexpensive and not too complex, and will allow you to make power poles that look prototype.
You can go as wild as you want, I see the challenge is getting it to look prototype and to carry sufficient power that one “line” can power many buildings, including perhaps some light animation.
Oh, Devon, the 48 volts can be a couple of simple transformers with a full wave bridge rectifier. The reason I say couple is you need about 35 volts AC, and it might be easier to get a 24 volt and a 12 volt transformer and hook them together… 36 volts with a full wave bridge and a filter cap will be cheap… there is no need to get a fancy regulated supply… the DC to DC regulators will handle that…
Greg
Greg
OK, since there have been distractions and “noise” and more in-depth explanations, Devon and I have been communicating by email…
I will report that this can be done inexpensively (Devon found a 48v power supply for $27), and I have shown the link for the DC-DC inverters that will step down the 48 volts to 3 volts regulated for the LEDs.
Also, theoretically, the system could power 1,000 LEDs total.
Finally, after asking about gauge, I did some rough calculations, and for this type of power pole, the utilities often use 0 gauge (aught gauge) which is about .324" and changing to 1:29 brings it to 29 gauge wire, and I had guessed 30 gauge would be about right, so all of this will allow a completely prototype looking distribution system, that, like the prototype, can power hundreds of homes.
Greg
Don’t forget the distribution or service transformers for additional prototype fidelity. (https://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-smile.gif)
Yeah, no way to do that easily with real components. Thought that through.
The idea is using LEDs and designed for efficiency, so try to keep power-wasting resistors out of the circuit, and also to keep it simple a system to not worry about voltage drop along the lines.
That all equates to a regulated voltage in the buildings… so a transformer on the pole would not solve that issue, still need regulation. Now, if we could get the DC to DC regulators to fit in a scale size transformer “can” that would work, but too small.
So, there will be “dummy” transformers, but they will just feed the voltage through.
Greg
As Greg mentioned we have discussed this pretty thoroughly. I agree with Greg on using “dummy” pole mounted transformers with simple wire passing through them and then having real working transformers in the buildings. I powered an LED that has a resister and at 12 volts is just way to bright. With the adjustable DC to DC transformer in the building each building could be custom adjusted to a level of brightness that is appropriate.
I even have a plan to make a mold for pouring clear resin insulators in different colors for the poles. My father is one of the nation’s leading experts on glass insulators and was one a prominent collector. So he has helped me with deciding what would be the appropriate style. Should be fun once we get to wrking on it.
Devoning again?
David Maynard said:
Devoning again?
Maybe!!! I am not making any promises on when this will really get put into action. We had a shuffle in our house and the basement was taken from me and I have a new room. But that does mean i will be able to get a slow start on the indoor. But that’s mainly a winter deal. What it does mean is any more buildings that get made for the indoor will be made with this plan in mind.
Devon Sinsley said:
David Maynard said:
Devoning again? I have a new room.
Sean McGillicuddy said:
Devon Sinsley said:
David Maynard said:
Devoning again? I have a new room.
Gee, that looks familiar. And, looking at that, I have a foggy memory about a wrap around canvas coat, that closed in the back.
