0005 Wiring point frogs, point motors & LEDs: Planning
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- เผยแพร่เมื่อ 8 ก.ย. 2024
- I wanted to have point motors to switch points, each with an auxiliary switch controlling a relay to change both frog polarity and some route indication LEDs.
In this video I describe the necessary wiring between these components and work through the necessary calculations for which resistors to use with the LEDs. I also cover the logic for making the LEDs light only along the selected route.
I was greatly helped my several of the Electrical Engineering Basics videos from The Engineering Mindset: • Electrical Engineering...
Nearer the end I explain some gotchas that arose from how the Peco Electrofrog points work, and finally demonstrate the LEDs working (plus some malfunctioning of the auxiliary switching)
An alternative way of switching frog polarity is to use a microswitch instead of the built-in aux switch on the SEEP point motor. This mitigates the unreliable switching issue. The microswitch can either be mounted above or below board, dependant on where it is to be deployed.
Hi Philip,
Thank you for sharing your thoughts - as it happens just this weekend I finished fitting microswitches to replace the SEEP aux switches :) They'll feature in a future video.
Thanks,
Jonathan
Vf typ is shorthand for Voltage Forward typical. Meaning that you usually drop roughly that voltage across an LED. IF max is the Maximum current that the LED can safely handle before blowing. Its normal to settle at 50% of this value so in your example approximate 12 mA would be better. The LED lasts longer and is more resistant to voltage rising. so .....9.9 volt divide by 12mA gives 825 ohms. In this case i would use a 1000 ohm (1 K ) resistor. Power dissipation would be 119 mW (rounded up) so a 250 mW resistor would be ok but always over engineer for safety so find a 300mW or 0.5 Watt resistor. Carbon film would be best as wire wound have some unpleasant issues in model railways.... And yes, a CDU is a Big capacitor bank which works on D.C. A.C in is rectified to D.C and then charges the Capacitors. As the point motors (seep type) are a coil of wire with about 3 ohms resistance, the CDU is able to discharge rapidly through the solenoid with enough power to throw the solenoid. I have been designing something similar to yourself, using relays to switch points and LED signals, mimic panels. An interesting insight into this way of doing things but never work components at maximum ratings if you can help it. That way expensive components last longer and work better. I treat VF typ as the minimum voltage drop for that reason, i normally round up to (in your case 2.5 volts). Anyway i do hope my electronics expertise has helped. All the best
Hi,
Thank you for taking the time to provide comprehensive information :) You're the second person to mention that it's better to stay a long way clear of the max for LEDs (the other comment was on a different video I think) - that's definitely worth knowing, and I didn't come across it from the things I watched and read, but will definitely factor it into any new set up that I do! And it's good to know about the capacitor - I still hadn't found out for sure. Helpful indeed, thank you :)
I have just this week finished adding Bi colour 3mm red/green Led's to my own Bachmann set track layout. All glued to the underside of the bed. Wired in series, robbing track power from the jumpers and the electro frog, using two Bridge rectifiers, and the suitable resistor. And being DCC controlled I can move them about and change layout as I please without need to re-wire. I'm now trying to think of a way to set up traffic block lighting using a similar idea. Hopefully to only use a simple three wire servo extension led to link each modified 9" straight section so again everything will be hidden and modular.
Hi Russ, using the track power sounds like a neat idea. How do you control the lights to make them change one way or the other - does that happen automatically through the frog's phase somehow?
@@endoorrailway the points, turnouts are controlled through the DCC unit, so when I open or close the switch, the points themself change the frog power from either neutral,or phase. For each unit I use TWO Bridge rectifiers. Frog goes to one side of both, and track power goes to the other side of each. So if frog is switched , one "BR" has phase and neutral, while the other is feed both neutral, or both phase. Therefore turning one on, and the other off. Flip flopping between them as you change the switch. Bi colour LEDs have two pins, so reversing the polarity changes the colour,. LED'S of this type must be wired in series,. I found trying to use them in parallel I got a feed back going back though each LED and gave a mix of colours. Yellowish, as the other was getting a lower power set through from voltage drop of feed through the one before it. I hope I haven't rambled on to much. And Hello from little New Zealand
I can send you a set of photos if you are willing to share email address
That's really informative, thanks - I think I can see how that would work - I don't think I'd ever have come up with an arrangement like that without being told about it! Thanks for offering to send some photos - I've just set up an email account for this channel: endoorrailway@gmail.com, so some photos would be great, thanks :) I'm also amazed at how global the interest in British model railways is - literally the other side of the world!
@@endoorrailway model rail in general I think, LoL. And thanks for your kind words. I don't model anything in particular, just trying to think outside the box, and get the results I'm looking for without staying brand loyal. And cheaper is always a side bonus. Will get some photos to you within a day or so
@@endoorrailway emailed photos and a drawing with ruff description of workings earlier this morning. Hope it helps you out