Smoke Units and DC...

Some of you may remember that I picked up a Lionel TMCC Long Island Consol as a display model, tried running it on conventional AC (which it didn't do so well at all), so I gutted it and am now running it on DC. (Nice of Lionel to put DC cans in their newer engines...  

You also might remember me asking about the smoke unit, and was told that the output might be anemic at best, which it has been....until now. 

I have an AristoCraft "Train Engineer Walk-Around Control System". I bought this at one of the (rare) local train shows a few years back. I guess this thing puts full voltage to the track at all times, then feeds the engine via the remote. Kind of a "poor man's DCC":

IMG_20181120_092946604

 You hook it up to a power source (in my case an MRC Control Master VI)  turn the output on that source up to "full", and then run the train with the hand-held remote.  As soon as you begin to feed power to the track, the headlight comes on at full brightness, and then off you go. It has always worked very well with my DC-powered trains, in all scales. So it occurred to me that I might try this with the 2-8-0.

Sure enough, since the smoke resistor is now being hit with (in this case 18 volts) at all times, the smoke output is greatly increased; a lap or two around my test oval and I can see a slight "fog" of smoke hanging over the track. I'm not gonna say it's as much smoke as in some of the videos I've seen, but it is vastly improved.

In my ignorance of electronics, I guess I thought that the smoke resistor would only work properly if running off an AC source, but apparently it doesn't care if it's AC or DC.

As always, I don't know if this is of interest to anyone, but I thought I would share it just the same...

Mark in Oregon

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FWIW, 18VDC on the smoke unit with a 27 ohm resistor will result in 12 watts dissipated by the smoke resistor.  Normal maximum is more in the lines of 7-8 watts maximum.  The result will be good smoke for a short time, then as the wick gets caked, the smoke resistor will overheat and probably burn out.  It's likely you'll also notice the smoke unit PCB will start to get brown as it gets overheated.

Good smoke, but not for too long.

Good to know John, thank you; what is meant by "PCB"?

Since I can adjust the voltage from the MRC unit, perhaps I'll be able to strike a "happy medium". Plus, I ordered extra resistors from Lionel during their big sale, so if and when this one goes kaput, I have replacements at the ready. 

Mark in Oregon

Thanks John.

On this engine, the resistor is simply lying across the smoke unit "bowl", with the ground end soldered to the unit's mounting frame and the other soldered to the hot lead; no circuit board.  

FWIW, I changed out the power pack to a Troller "Autopulse" that puts out only max. 12 volts; the smoker is still putting out well when the pack is set at about 8.5V, so perhaps I'll be buying some time to the resistor by doing this(?)

Mark in Oregon

gunrunnerjohn posted:

FWIW, 18VDC on the smoke unit with a 27 ohm resistor will result in 12 watts dissipated by the smoke resistor.  Normal maximum is more in the lines of 7-8 watts maximum.  The result will be good smoke for a short time, then as the wick gets caked, the smoke resistor will overheat and probably burn out.  It's likely you'll also notice the smoke unit PCB will start to get brown as it gets overheated.

Good smoke, but not for too long.

Hi john

What are the typical voltage requirements for TMCC & Legacy smoke units.  Do most TMCC & Legacy smoke units fall into the 7-8 max wattage limit.

Thanks,

Bob D

 

 

 

That's what I generally see to produce good smoke.  When I'm testing, I use straight DC on the bench so it's easy to compute the power in my head. Generally I find by the time you get to around 8 watts, you're getting lots of smoke!  I actually "tested to destruction" a smoke unit once, I ran it with 12 watts for an extended period.  Even keeping smoke fluid supplied it managed to really coat the wick and reduce the output within about half an hour.  If you don't keep it wet at 12 watts, it'll smoke the PCB.

gunrunnerjohn posted:

That's what I generally see to produce good smoke.  When I'm testing, I use straight DC on the bench so it's easy to compute the power in my head. Generally I find by the time you get to around 8 watts, you're getting lots of smoke!  I actually "tested to destruction" a smoke unit once, I ran it with 12 watts for an extended period.  Even keeping smoke fluid supplied it managed to really coat the wick and reduce the output within about half an hour.  If you don't keep it wet at 12 watts, it'll smoke the PCB.

Forgive me for asking this:  

3 times in this post you use the term "watts": during these tests, how many volts are you using? Doesn't that figure into the equation as well? (Guess I really need to figure out this "Ohm's Law" thing!) 

Mark in Oregon

Volts * amps = watts, this is true when you're dealing with DC or pure sine wave AC voltages.  If you're dealing with  You can have 8 watts with one volt at 8 amps, or 8 volts at one amp.  Here's a shortcut for you, the Ohms Law Calculator.  Enter any two variables and it'll compute the other two.

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