So I have this non powered ps-1 centipede. All components removed, except for 2 smoke units and the lighting board. If I want to pull it around the layout with the smoke units turned on, I would like to know how to limit the voltage to the smoke units. I would normally be pulling it with 18 volts on the track as I use DCS and TMCC/Legacy. At 18 volts smoke is just too much. When I lower to 9 volts I get just the right amount. So what components do I need to limit the voltage going to the smoke units. I am thinking I may have to insert the component between the smoke unit switch and the positive wire going to the smoke board. Here is a few pics. One pic shows way too much smoke and the other shows 9 volts applied on the track. 9 -10 volts is what I am looking for. I am guessing I need some kind of voltage regulator. The 2 smoke units together draw about 2 amps (displayed on my z4000. If someone knows what I need, can you please be specific with item #'s and where to get the item. Thanks in advance
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Thanks John....Seems to me I did that before for other applications and seem to remember voltage only dropped about just a little less than 1 volt. So I had to start putting diodes in series. So can 1 diode really drop voltage 9 volts? I am attempting to go from 18 volts down to 9 or 10 volts. you know better than I.
Here is a few pics of my attempt to get this smoke unit voltage down to 9v from 18v track power. Bought these diodes off Ebay. Hooked 1 into the circuit between pickup roller and the smoke unit. It really didnt slow it down a bit. I ended up putting 10 diodes in series to get the 9v I was looking for. This is an ugly looking bank of diodes. I guess I am doing something wrong. Any input please?
The "direct" approach would be to simply replace the 16 ohm resistors with a higher value. I'd probably start with 22 ohm resistors in one and see how that worked. You could retain one diode to lower the voltage and the higher value resistors should make a substantial difference.
Part of your issue is that when you lower voltage that circuit board cuts out one resistor and you get a 16 ohm single smoke unit. When voltage rises the second resistor is placed in series and you have a 32 ohm smoke unit. So while you are cutting the voltage with your diode string you also are shifting to a lower resistance which also means more smoke. You need to measure the DC voltage out of the rectifier with your set up. If you leave smoke resistors alone you want to target a voltage high enough to keep the 2 resistors in series for 32 ohms. So probably around 10-11 Volts DC out of the rectifier. Or leave the smoke board alone at track voltage and change the resistors to something like 22-24 ohms for a total around 48. Figure out what you like. Otherwise get a variable voltage board that can drive the smoke unit at a selectable DC voltage you can set. See what you like. You also can use a diode to slow the smoke fan motor down. It does spin faster at higher voltage despite the 5V regulator. G