RailPro > RailPro Specific Help & Discussion
Frog Juicers compatible with RailPro?
TwinStar:
Bill and Alan:
Not what I wanted to hear but I can understand. If a design, part numbers, or a kit was ever assembled I'd be all over it and just build my own. The problem is that I'm a very short bus electrical guy. I need lots of part numbers and colored instructions.
G8B4Life:
--- Quote from: Alan on July 20, 2018, 12:01:46 PM ---Tim, there is no need for zero stretching (with a booster or with the new PDC converter) unless you are operating DC locos. RP modules rectify the track power so all AC frequencies and duty cycles produce the same result inside the LM.
--- End quote ---
Alan,
If you read my reply again you'll see that I was saying that the circuit design by Rob Paisley generates a zero stretched signal but one would want to change that to the normal DCC signal by changing the component values, but it could possibly work as is anyway.
Continuing on this discussion because it is interesting, Robs design is the closest thing I found to a usable circuit for driving a DCC booster without an actual command station, though there are a few questions that I'd like to ask him about it.
I did some looking at the relaxation oscillator design online and found a few designs that provide the necessary swing from + to - and back again ad infinitum but with all of them they don't provide the opposite phase required for correct output to the track for using directly (see the right hand side of Robs circuit). I don't know how one would make it work without even more circuitry on the oscillator part.
This is a link to some designs on some forum on creating a square wave AC signal, with the relaxation oscillator design given a few times (probably only of interest to Alan): https://www.edaboard.com/showthread.php?292062-Dual-polarity-square-wave-generator
Edit: Reading the NMRA standard for Power Stations (Boosters) you should be able to drive a booster with a unipolar signal from a relaxation oscillator fairly easily (a bipolar signal would be harder, a bipolar signal has to present to the booster differentially across the inputs of the booster). https://www.nmra.org/sites/default/files/standards/sandrp/pdf/S-9.1.2_2012_07.pdf
- Tim
Alan:
--- Quote from: G8B4Life on July 21, 2018, 03:40:44 AM ---Alan,
If you read my reply again you'll see that I was saying that the circuit design by Rob Paisley generates a zero stretched signal but one would want to change that to the normal DCC signal by changing the component values, but it could possibly work as is anyway.
- Tim
--- End quote ---
My apologies. Brain saw zero stretching and jumped to a conclusion.
--- Quote from: G8B4Life on July 21, 2018, 03:40:44 AM ---I did some looking at the relaxation oscillator design online and found a few designs that provide the necessary swing from + to - and back again ad infinitum but with all of them they don't provide the opposite phase required for correct output to the track for using directly (see the right hand side of Robs circuit). I don't know how one would make it work without even more circuitry on the oscillator part.
- Tim
--- End quote ---
The circuit I showed is just a basic oscillator and was included since the message was introducing oscillator into the discussion for the first time. Yes, additional components would be needed in a final design. The inverse output (as you note), output driver transistors, and overload protection are a few obvious needed additions.
Regrading the inverse output, that could be accomplished any number of ways. You could simply add a second oscillator 180 degree out of phase to the first. Or you could add a logic NOT gate (inverter) tied to the oscillator output to get the inverse. Or you could do it in with the output transistors themselves - P channel and N channel outputs similar to audio amplifier output stages although this approach would require fine tuning to manage DC offset but it could be done. Point is the task of creating an AC square wave is not revolutionary. It is quite common in many electrical devices.
[EDIT]
Realized an easy way for everyone to visualize the DCC-simulation power supply - Consider the inverters sold for cars, campers, and boats so people can run 115V AC appliances from the vehicle's 12V DC electrical system. The DCC-simulation power supply would work the same except at different voltages of course and instead of outputting a sine wave it would output a square wave. Otherwise, same same.
Alan:
Hmmm... inexpensive starting point:
https://www.ebay.com/itm/ICL8038-Function-Signal-Generator-Module-Sine-Square-Triangle-Wave-Output-Kits-S/401386381107?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160727114228%26meid%3D61d19766d757442cb4f60dd17abf03e3%26pid%3D100290%26rk%3D3%26rkt%3D4%26sd%3D201835571136%26itm%3D401386381107&_trksid=p2060778.c100290.m3507
BruceRogers:
I've been using Ring's AR-1 as a frog juicer. Works perfectly even though it's a little pricy, the frog can be connected to either RT1 or RT2 output.
Tim Ring says the RT1 is the strong output from an electrical point of view.
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