I’ve been digging through the site and trying to decern what I would need to give my switches (5121/5122) dedicated power with panel lighting/ and or accessory lighting. From what I can tell I need to tie into the coil wiring for the switch, add capacitive-discharge circuit then add dual coil latching relay for the lighting. I have made a sketch to mockup my plan but want some insight from the more seasoned members on here. Please look at my Very Basic sketch and let me know if I’m OK or way off base.
I will connect everything with jumpers prior to soldering and installing as well.
The diode-resistor-cap arrangement is not a capacitve discharge circuit, it’s a half wave rectifier with filtering to provide DC to the relay and leds. As long as the toggle switch is a SPDT momentary type in each direction with the center OFF, you don’t need a C-D circuit anyway. Both the turnout and relay will only be energized while holding the toggle in one direction or the other.
The 10 ohms (and 100w is way overkill here) isn’t doing much for us. If the “Control Panel Lamps” are indeed leds and they are not specifically listed as having internal resistors, you need a much higher value than 10 ohms to not burn them out. With the 14V, that could be from 750 ohms to 1.5K ohms, give or take, depending on how bright you want them. 1/2W or larger is fine for that value resistor range and the 14V. That higher value will cause issues with throwing the turnout, so just remove the resistor from where it is. Instead, the red connections at the relay would go through your new resistor to the center terminal on the toggle switch.
If you are one of those people who are bothered by different color leds not being the same intensity with a common current limiting resistor (I’m one of those people…) you’ll need to install individual resistors in each of the green and orange wires from your leds to the relay and eliminate the single one going to the wiper of the relay contacts.
Thanks for the response. Typo on my end. The Resistor should read 100 ohm, 10W, which I thought would lower the voltage during switch operation so as not to burn out the switch motor then charge the cap in-between switches. My concern is not the momentary switch but rather rail cars stopped on the switch(s). I did think there might be a need for secondary resistors for each LED for even smaller voltages as well. With the 100 ohm resistor in place of the 10 ohm resistor drawn, and a 1k resistor feeding the relay contact common, how would that look?
The difference a value makes! OK, I see what the approch was. Something I overlooked the first time, though… are you also using the KW as your train running transformer? When the train goes over the control rails on the switch it’s going to connect the outside rail (which would be the KW’s U) to the switch coil (and the relay coil) with a 20V AC potential (D to U). That just goes around the rectifier and discharge circut.
There’s no KW combo that allows roughly 14V while letting the switch reference the U terminal. I think the easiest solution is to get a smaller transformer to use for the switch power, phase it with the KW, and use that as your 14V. If you have to use a variable terminal you can probably pull the handle off so you don’t accidently move it. The C-D circuit would go between the other terminal of the new source and the switch and relay coils - note any polarity change at the relay. The center wiper on your toggle goes to the new commom of U and the switch power so it is switching the same potential as a control rail. Then it’s just tweaking values of the R & C to get good switch operation, recharge time, and current limit for any continous control rail activation.
Thanks for the reply. I didn’t think about the possibility of the 20V interference. I will have two transformers for this now and make sure they are phased correctly. I also might use dedicated resistors for each LED to ensure correct brightness.
