LIQUID SMOKE

[ERNIE PRR]

I have a new 0-6-0 switcher with light and smoke, product code 50614, that I bought on-line. The light works, but the smoke dosen't, even with the supplied smoke or the smoke that I bought from my hobby shop. My hobby shop says that there isn't anything wrong with it. they put liqiud smoke in it and it puffed once or twice in a minute or so. my question is this. Is that the way it is supposed to work normally and that is what i can expect, or is there something wrong with it?  I would expect to see it puffing smoke as it trzvels down the track.
Thank you,
Ernie

[Stephen D. Richards]

Is it DC or DCC?  If it is DC then the more power you apply, the more it will smoke but it doesn't quite work like the real thing.  On DCC, it will puff up a storm even at idle.  The faster you run on DCC the less you can see of the smoke.  It is still producing smoke but only at a constant rate and it kinda dissipates faster at speed than idle.  Hope that gives you some idea.    Stephen

[bevernie]

 ;DGREETINGS!!
Stephen, your statement that "If it is DC then the more power you apply, the more it will smoke..." caused me to wonder... will a "constant lighting circuit" cause it to smoke at a more constant , and noticable, level?
    Just wondering!!!
                                                                                           THANX!!
                                                                                           Ernie

[Stephen D. Richards]

Yes sir it will.  I guess you could even regulate the amount of current applied and make it smoke more realistic!  I'll have to experiment with that or maybe Jim Banner may already know.  Stephen

[Jim Banner]

Direct current (dc) constant lighting circuits work by using low voltage bulbs and one of several methods of regulating the voltage to a low value.  This way, the bulb can have full voltage at low track voltage but not excessive voltage at high track voltage.  Constant lighting circuits cannot boost the track voltage.

Enter the smoke generator.  Most designs allow for people running their locomotives at full speed (maximum track voltage) without smoke oil in the smoke generator and still not burn it out.  This means the engineer who like to run a scale speeds is not applying enough voltage to make the generator work properly.  Unfortunately, adding a constant lighting circuit will not boost the voltage at low speeds.

One alternative already mentioned is operating on DCC which uses constant voltage on the track.  Another is to replace the smoke unit with one designed for a low voltage, then add a voltage regulator to limit the voltage to the smoke generator.  Others may be able to advise you on the availability of low voltage smoke units - the only ones I know of are used in large scale locomotives where the extra current doesn't make much difference.

Why don't the manufacturers do this in small scale locomotives?  The answer is that for a smoke generator to work, it needs a minimum amount of power.  Power is amps times volts.  If you reduce the voltage, then you need a proportional increase in the current (amps) rating to keep the power the same.  Take a smoke unit rated at .1 amp at 16 volts.  It uses 1.6 watts when working really well.  Replace the heater in that smoke unit with one designed to run at 3.2 volts.  Now you need to put .5 amps through it to make 1.6 watts of heat and have it work really well.  Most power packs can put out an extra .1 amp in addition to the current required to run the motor.  But a lot of low cost train set power packs can only put out .5 amps total.  That is, your low voltage smoke unit could make lots of smoke but not leave enough current to make the locomotive move.

These are the engineering considerations for making better smoke.  The sales department would never stand for it.  Word would soon get around that to run Brand A with smoke means you have to pay more for the locomotive (remember the voltage regulator) AND you have to buy a new power pack while Brand X smoking locomotive is the same price as a non-smoker and you don't need a new power pack.  So we continue to have mediocre smoke units.

Jim   

[Stephen D. Richards]

Jim, that makes sence but I was considering maybe cutting back the power a bit on DCC to make it a bit more realistic smoke and not just sputtering out the fluid.  I'm not sure I can accomplish that but it is interesting to consider.  Stephen

[Jim Banner]

Cutting the power down when using DCC is easy.  Just add a resistor in series with the smoke generator.  Start off with a 100 ohm 1 watt pot in wired as a rheostat in series with the smoke generator and adjust the pot until you see smoke the way you want it.  Then measure the resistance of that half of the pot. Buy a fixed resistor close to this value of resistance and rated at 2 watts or more.  Finally, install this resistor in place of the pot.

Jim

[bevernie]

 ;DGREETINGS!! :oOn page 63 of "PRACTICAL ELECTRONICS PROJECTS FOR MODEL RAILROADERS" by PETER J. THORNE, is an article, including schematic and parts list, for a "HIGH POWERED LIGHTING GENERATOR", as opposed to a "CONSTANT LIGHTING CIRCUIT".
Though yet untried, this seems like a very viable possibility for a smoke unit, since it doesn't depend on track voltage! From the article, it seems that this was designed for use in passenger car lights, but it LOOKS like it can be used on a smoke unit... another "plus" is that it is connected to the TRACKS and not to the SMOKE UNIT, so, therefore, it is NOT IN THE ENGINE!!
    The only drawback is something about this cannot be used in a "REVERSING CIRCUIT".
    Still, I'm thinking about trying it, as soon as possible!
                                                                                                   THANX!!
                                                                                                   Ernie

[Stephen D. Richards]

Jim, thanks for the info.  I will give that a try. 

Ernie, hope that works and if it does let me know!

Stephen