I have a turnout that I will be controlling from a NCE Switch- It. I know how to wire the red and green turnout position LED control panel indicators in parallel in one of the connection leads from the Switch-It. I have two additional control panels on which I would like to have the same turnout position indicated, requiring two additional LEDs of each color (three red and three green total).
So my question is can I just wire the additional LEDs in parallel with the originals, or will this have an adverse effect on the operation of either the Switch-It or the Tortoise? I'm aware that I can use the contacts on the Tortoise to accomplish this but I'd rather not.
Thanks
You can also wire the LED's in series with either pin one or pin eight of the Tortoise motor, or is this how you are wiring them now?
If the voltage from the switch-it to the motor is 12 volts, you should be able to wire three or four LED's in series for each direction indication and they should work OK.
That would be: two LED's in parallel back to back, in series with two more in parallel back to back, in series with two more in parallel back to back; giving you three parallel back to back sets in series with each other on the same motor wire.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
So this boils down to 2 LEDs in parallel with each other but reversed polarity, and both those are in series with the turnout motor. The 2 LEDs are using the turnout motor as the load on the circuit hence no resistor.
That circuit will not draw any more current than the turnout motor demands. It is not going to add any more load to the Switch-It. So your answer is that it depends on the current draw of the turnout motor. If it is drawing enough current to light multiple LEDs then yes it the other panels' indicators can just be put in parallel. If the turnout motor is not drawing enough current, adding the second LED (or third for that matter) will dim them all. I would just us aligator clips to put one temporarily onto the circuit and see if they are sufficiently bright enough for the situation.
If not, then consider putting the LEDs in series with each other. This will lower the voltage to the turnout motor but I believe most stall motors will drive from as low as 9 volts. It will still be a pair of wires to each panel whether parallel or series.
If it was anythign but a Switch-It, I'd say just stick more LEDs in the motor circuit, but the Switch-It is already on the low side when it comes to voltage. The current isn;t a problem, the whole circuit will draw no more than the Tortoise motor, however each LED adds voltage drop - depending on the LED,1.6-2.1 volts. This is great when running the Tortoise on 12V, as 12V is a little high anyway, they are much quieter around 9V. So you stick in an LED or two, and boom, perfect. You can;t up the voltage of the Switch-It though. If you wanted to run 3 or 4 pairs of LEDs on each Tortoise with a regualr power supply, you could alway sup it from 12 to 14 or even 16 volts (of course you'd need the same number of LEDs with EVERY Tortoise - but 3 pairs would drop 16V to a little over 10V, or 14V to a little over 8V, perfect for a quiet Tortoise.
For lots of extra LEDs with an already low motor voltage, you'll probably have to resort to the contacts ont he Tortoise and some power supply, plus resistors for the LEDs. Resistor value will depend on the power suppyl you use. You can run a LOT of LEDs off one set of Tortoise contacts without exceeding the limits on the contacts.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
gandydancer19 You can also wire the LED's in series with either pin one or pin eight of the Tortoise motor, or is this how you are wiring them now? If the voltage from the switch-it to the motor is 12 volts, you should be able to wire three or four LED's in series for each direction indication and they should work OK. That would be: two LED's in parallel back to back, in series with two more in parallel back to back, in series with two more in parallel back to back; giving you three parallel back to back sets in series with each other on the same motor wire.
Elmer:
Yes, I set up an experimental circuit that was wired as shown on the Tortoise instructions. One output from the Switch-It went directly to the Tortoise, and the other output went to the parallel (green and red) LEDs and then back to the other Tortoise connection.
I'm confused by your second paragraph, I think. Can I put the three red LEDs in series with each other, the three green LEDs in series with each other, put the two sets of LEDS in parallel, and then insert the combination in series with the other motor lead?
And what would happen if I put the three LEDs in parallel with each other, and put the two parallel sets in series to the motor lead?
The following scan is (hopefully) a sketch of what I think are the three options. I think option 1 is what you described. Will either of the other options work, or is there one that won't work?
Option 1 is the 'usual' way to do it. Option 2 is equivalent. Optipn 3 will not work, or if it does, each LED will be very dim since the three LEDs are in parallel and thus share the 15ma or so of the Tortoise.
I don;t think ANY of them will work with a Switch-It, as the voltage out of them is already 9V or so. Dropping through 3 LEDs will leave maybe 3V for the Toroise - I think that's a bit below what it can work reliably at. 6V is about the absolute minimum for it to have any holding power.