weird smoke problem

[sulafool]

You've all heard of engines that run better in one direction than the other........how about an engine that smokes better running in one direction than the other??

I have a 2037 with a new pill type element that does just that. It smokes better when the engine runs backward. Makes no sense to me; I've tried all the usual tricks one does for the "running faster" situation, with regard to brushes, spring tension, etc. and even swapped wires from one brush to the other.

Not a mechanical cause, for I can put the engine on rollers, remove the drive rod/crosshead, and pump the smoke rod with my finger while cycling the motor between forward and reverse and observe the phenomenon.  This difference is clearly noticeable.

I measured the current thru the engine while spinning both ways and the difference  is only a couple hundredths of an amp (1.61 and 1.63). Can't believe that would be enough to cause it.

Anyone else seen this before? What's the fix? I could live with it if more smoke was produced going in the forward direction, but Murphy decided to mess with me and now I've become obsessed with the mystery.

Any ideas or suggestions?

[rtraincollector]

This may sound crazy but it a wild guess how about reversing the wires on the smoke element to see if does anything . Probably not but just an idea in the dark lol

[SantaFe158]

There would only be one wire going to the smoke unit and unless it was a fan driven unit, it really wouldn't do anything. I can't really think of a reason for it not to work in forward though. Real odd problem.

[lionelsoni]

Is it possible that the smoke generator is wired to one of the brushes rather than to the pickup?  That would give it full voltage in one direction and only the field-winding voltage in the other.

[SantaFe158]

Good point. I'm pretty sure the smoke unit in my 2037 is soldered to the power feed for the E unit (so basically hooked up to the pickup roller). That's probably your problem.

[initagain]

So far, everybody is relating the problem to something electrical.  If it smokes at all, the wiring is probably correct.  Something to consider is how the smoke puffer is assembled.  There should be a drive link that is activated by the eccentric rod on one side of the locomotive.  Rather than trying to explain here how it is assembled, you can probably find an exploded drawing on Olsen's parts website.  If the drive link isn't seated properly, the smoke will still be produced, but the puffer assembly won't work in one or the other, or both directions.

[lionelsoni]

The crank that pumps the smoke is pushed by the crosshead, which is moved by the main rod (there is no eccentric crank on a 2037) and travels the same distance whether the locomotive is going forward or backward.  In any case, he said he pumped it by hand with the crosshead and main rod removed, just to eliminate this possibility.

I don't know why the locomotive is behaving as it is; but I do not see why we must rule out an electrical cause if it smokes at all.

[sulafool]

Yes, it is wired to the e unit/pickup roller.  The only thing that makes sense to me is that the motor is hogging more current when running forward, but, as I said, my measurements indicate only a negligible difference.

To my eye (lacking any usable instrumentation to prove otherwise) the engine appears to run at the same speed going either way.

[sir james I]

The only reason it would smoke better going backwards is that it is taking more voltage to run in reverse than forward. Try adding a few more cars to put more load on the engine.

[lionelsoni]

The smoke generator is sensitive to track voltage, not motor current.  You may be running at different voltages in the two directions, even though the currents and speeds are the same.

[sulafool]

OK, but since the smoke is connected to the track pickup and "ground" it doesn't go thru the e unit but parallels it, yes?

[lionelsoni]

I meant "smoke generator" but typed "e-unit".  I just now edited it for future readers.  Sorry for the confusion.

[DMUinCT]

Could be the Locomotive "scoops" more air into the locomotive body shell running backwards, very little chance of air flow running forward?

[lionelsoni]

The wheels are turning; but the locomotive isn't moving in his test.

[sulafool]

Just measured joltage at the smoke unit; measures within 0.1 volts of each other. If I can figure out how to take pictures that will show the smoke, I'll post them .