Hello Looking at the 2nd circuit (on the right, with the 2 leds)...........Is C1 needed or not? I think it is needed and part of the power supply...it's just not represented on diagram #2? Can someone confirm?
All it is doing is buffering the power coming from the supply. It should be there always (think of the feed to "N" on the left circuit as going up to the top line; C1 is parallel to both circuits) if you want to make sure there are no power drops. I am more concerned by the note "C2 = 2 to 3 times C1", yet on the drawing it is the exact opposite
Keep in mind that the movement to one position is solely from power supply power and the movement to the other position is made by the smaller capacitor discharging. As such, C1 is there to buffer (as Rick wrote) the power supply, but the power supply itself is the most important component for power -- it has to be strong enough to move the solenoid, i.e. don't get hung up on the importance of the capacitor. By the way, 4400mfd is high. 2200mfd is sufficient for Kato turnouts and it may not be needed at all. C2 is what throws the solenoid in one direction. 2200mfd is overkill for single Kato machines. 1000mfd is sufficient. Years ago Rob Paisley and exchanged some e-mails regarding his circuit and this is what I ended up building. I did not use a power supply capacitor, as I'm using an ample solid state supply. I used a 1000 Ohm resistor (instead of the 2200 Ohm as shown) to tone down the light level from the LEDs. The diode shown is perhaps optional, but I added it. It might prevent the capacitor from discharging back through the solenoid coil when another machine is worked and moving a solenoid that's not being thrown. With 24 turnouts, I didn't want to risk trouble. Your best option is to mess around building some test circuits and see if you like the result. Here's the backside of my panel with this circuit:
Cool, thanks for the info......I have a 15V/16A power supply that I use to power my battery chargers I will give it a try with 1,000uf and see how it goes Is 35V necessary, or 25V should be sufficient?
I went with 35V, though I'd think that 25V would be fine. That's QUITE a power supply you have there. It's DC, right? I hope it has a fast-acting circuit breaker. Otherwise, at 16A it'd rapidly vaporize everything.
Here's the front side. Because I wanted to make my control panel as slender as possible to save space, I'll be mounting the capacitors near each turnout.
WOW thats a nice panel . i really need to build something like this. Thank You for the pics. its very nice
I understand you don't use the C1 capacitor, but looking at the picture, I have a question: I can clearly see the resistor and the diode installed on each switch, but where did you put the C2 capacitors? Do you only have 1 capacitor per row (1-8, 9-16 and 17-24) so only 3 in total?
I put the discharge capacitor for each turnout near the turnout location. I did this only because I didn't have room to place them within my control panel.
Just a clarification regarding post #4: all the diagrams in this thread use capacitors spec'd in microfarad (uF, using the 'u' instead of the greek 'mu' symbol), not millifarad (mF). 2200 uF = 2.2 mF. Fd is Faraday, a charge unit.
For me, it's clear we were talking µF, and didn't even pay attention that post #4 was using "mfd" and could be understood as millifarad
The late G Ray Stilwell, Jr designed a similar circuit described here: https://www.trainboard.com/highball/index.php?resources/g-ray-stilwell-bcd-circuit.153/ See Figure 2. It uses only an SPST switch and a single bicolor (bidirectional) LED. You could use separate diodes if desired. Note the capacitor is in series with the switch machine coil, so it can go between the switch and the (grounded) coil, or between the coil and ground. Wiring may be a little simpler if the coil is grounded.
With 1,000 Ohm resistor, you only have 10ma in green or red LED, right? (and ~5ma with the original 2,200 Ohm resistor) Are they bright enough? i usually calculate the resistor to have 20mA in LEDs........(~560 Ohm)
Yes, I dimmed them down. I recommend that you test various resistor values to find what works best for your eyes and room lighting.
Well, the best thing to do is to experiment with the particular LEDs you are using to find the brightness you like, to account for LED design and personal preference, but I would say most are plenty bright at 5-10 ma.
