Smoke in a three truck shay. (SOLVED)

[bobgrosh]

SMOKE!
Or lack of it.

From 9 to 22 volts DC on the rails I get about 6.5 volts on the two pink wires. With the smoke switch on, and the provided smoke fluid, I sometimes get a whiff of smoke out the short stack or the cabbage stack. I get no smoke from the big stack. Smoke does accumulate in the bottom third of the big stack but it never fills up the hollow stack and exits the top.

I've tried starting with just a few drops of Bachmann smoke fluid on the heating element and added a few drops at a time until the reservoir was nearly full. The amount of fluid makes no difference, nor does the track voltage once the voltage is above 10 volts DC. I made my observations with the motor switch in the center position so the lights and smoke were on with the loco stationary. Compared to other locos I'd say this one just does NOT smoke.

According to the connection diagram, the cab light and smoke generator are both supplied by a voltage regulator.

The cab light is so dim that one has to raise the cab roof hatch to see the actual bulb to tell if it is on. When on, the filament itself glows with an orange glow but does not produce enough light to illuminate the inside of the cab, even in a dark room.

With the track switch in the center position to disable the motor, the headlight, reverse light, and cab light come on. With the smoke switch OFF, I measured the current draw with 20 volts on the rails. I measured it again with the smoke switch ON. The difference was about 45 ma. I got the same difference when I repeated the measurements with 12 volts on the rails.
From the above I concluded that the smoke unit draws about 45 ma. Compared to other 5 volt regulated smoke units that I've measured this is very low. Most brands of smoke units draw from 100 to 250 ma.

There is a unused screw terminal on J3. It is not used at all for DC or DCC according to the connection diagrams. There is a white jumper from the board to the other terminal on J3, there is a three volt difference between the two terminals. Is it possible that this is a course adjustment for the voltage regulator. Will moving the jumper increase the voltage to the smoke unit and cab light? Just wondering, as there does not seem to be any other adjustment or option jumpers on the board.



Is there some easy way to increase the output voltage of the regulator to provide a little more smoke and light in the cab.

B0B

[Curmudgeon]

No, and no.
The regulators used are 12V, but, as you discovered, that ain't what they put out.
You haven't dealt with Bachmann non-smoke units much, I would surmise.

Feel yourself fortunate that it worked at all.
Increase the voltage and it will work for an even shorter time.

I use a Seuthe 18V unit in the metal tube of the cabbage stack,
I cut off, oh, 3/8" and ream the end a bit, and run it off battery power.

Cab lights are not supposed to light up the countryside.
I have had most on earlier Shays and Climaxes flicker under the influence of the load of the flicker drivers until the components warm up.
Build your own regulator or put one of those wimpy yellow LEDs and a dropping resistor in place.

Welcome to the world of Bachmann.

[Paul W.]

One of the posters on this board posted this video earlier this year

http://www.youtube.com/watch?v=hz9m0LUCJ0g

He was running DCC, but I don't know if he changed smoke units.

[bobgrosh]

That is great smoke!. 
I'm not even getting 1% of that.

One has to stare at mine for a while to see even a whiff.
On the good side. with the unit 1/4 full, it lasts a full day. And then some.

[bobgrosh]

OK, the smoke unit presented a challenge and I accepted it.

Took it out.
Connected it to variable supply and meter.
At 6.5 volts it does not even get warm enough to feel the heat when I touch the bare coil
Raised to 12 volts. A little more smoke now but the coil is not glowing and there is no percolation effect through the center tube. The smoke is still hardly visible. At 16 volts, still no more smoke and the coils is starting to glow.

Then I saw a problem.
The only smoke generated was coming from the outside of the tube where the surfave of the oil was touching the coil.
The center tube is smashed closed at the top. No smoke was coming out of the tube.


I used a thumb tack to try to open it up. Managed to get it opened a little but still no luck.

I pulled out the center tube and after fighting it for a while, I managed to get the inner rod out of the tube. (The inner rod looks to be an extra fine piece of mechanical pencil lead and is used to create the capillary action to lift the oil into the tube.)

I sanded away the collapsed part of the top of the tube and got a fine wire to pass through the tube.

I left just enough of the crip at the top of the tube so that the inner rod would not be blown out throught the top of the tube when the oil is percolating.

I inserted the rod into the bottom of the tube. Then, I inserted the tube through the clear insulator and nichrome coil into the white cup, pressing it firmly onto the sloted hole in the botton of the cup.

I Applied 7 volt, still no percolation up through the tube.
At 9 volts I got a little percolation and much more smoke , but still not as much as in the video.

I raised the voltage to 12 volts. Perfect, I now have as much as is seen in the video.

I turned out the lights, the coil was not glowing. Raised the voltage until the nichrome wire started to glow a little. (17 volts) This did not increase the smoke volume as the tube was probably too hot and the oil was just being blown through. It was splattering unused (un-burned) oil. I lowered the voltage to 12 and everything seems to be percolating at about the normal rate I've seen on other working smoke generators.

I emptied the white cup,waited till the smoke stopped and put 5 drops of oil in. I repeated this experiment at 1 volt increments between 10 and 16 volts. I decided that 12 to 13 volts provides a reasonable amount of smoke. 14 volts produces very little more but produces some oil splattering. 15 volts produces no more smoke than 14 but uses up the ten drops of oil in half the time.

Now all I need to do is connect it to a function output I can control the voltage on, and set the voltage at the generator to somewhere around 12 or 13 volts.

Problem solved. Thanks for the help.