Yet another Locomotive Project

[jbrock27]

Thank you for your answer Jonathan.
Looking great!

[Irbricksceo]

Looks Great! I'm  curious, Did you wire the light to turn on in both directions?

[jonathan]

Again, thank you.

The reverse light is a Surface Mount LED (SMD).  It will turn on in only one direction.  Hence, the positive lead is wired to the tender frame.  The negative lead, with resistors, runs to the frame of the locomotive--wired backwards from the headlight.

Moving forward the headlight is on.  Moving backwards, the reverse light comes on and the headlight turns off.

With this simple-type wiring, I ocassionally get what I can only attribute to a static build up (guess).  In other words, every once in a great while, the reverse light will flash while the locomotive is moving forward.  Strange... not really noticable when hauling a consist.

Regards,

Jonathan

[jbrock27]

I have had that happen occasionally, on some of the diesels I have wired this way.  I thought my eyes might have been playing tricks on me when I would see a very brief flash of the light at the opposite end of the direction the loco was going in and wondered why this would sometimes happen.  Otherwise, the directional lights operate as they were set up to.

[Irbricksceo]

Well, even with SMLEDs you could do it in both directions, but it would required diodes and be more trouble than its worth IMO. i've never seen this phenomenon you describe but It is curious.

[electrical whiz kid]

Jonathan;
I have found that taking the time it takes to be excruciatingly fastidious pays off-I have done it most ways, and that is best.  For that reason, I decal on a rainy day, when I am totally relaxed.  I use a scalpel for doing decal work-it touches NOTHING else.  I had been using Floquil paint until they dropped the "good stuff" (the organic lacquer) so will start looking for a good gloss coat, and a relly really dead flat.
On the decals:  I try to make my cuts at the lettering as much as possible.  This helps tremendously, and the film won't  tend to show on the rest of the decal (optical illusion probably).
RIch C .

[jbrock27]

Rich, what method or trick do you use, when you cut at the lettering, to get all the letters to line up on the same axis?  Thank you.

[Joe Satnik]

Dear All,

Had your coffee yet?  Good.

Welcome to (old school) Electrical Engineering.

The reverse diode flash is caused by inductive kickback from the motor.

Any inductor, which includes a motor winding, is an energy storing device. 

It stores its energy in "current" (I), which is measured in Amps.   

Just the opposite is a capacitor, which stores its energy in "voltage" (V), which is measured in Volts. 

It is hard to get current going in an inductor. 

Once you get it (I) going, it wants to keep going. 

If you abruptly turn off the power to the inductor, it will try to keep the current going. 

https://www.youtube.com/watch?v=auvh0H4QvbY

That current has to go somewhere. 

In this case the reverse LED happens to be (conveniently) available to absorb (provide a non-destructive path for) that current, thus the flash. 

If your front LED is wired to run only in the forward direction, you will see it flash after you are running in reverse and abruptly turn off the power.

Inductive kickback can destroy sensitive electronics,

so in many cases reverse diodes are wired across inductive loads to absorb it. 



You may wake up now. 

Hope this helps.

Sincerely,

Joe Satnik

[ebtnut]

BTW, Jonathon, I have one of the original Weside B&O Q-4b's.  I remotored it very early on with a big Sagami that just fit inside the firebox.  When our club decided to go to command control (with CTC-16 so you know how long ago this was) I wanted to run the loco there.  As with most Vandy tenders I've run across, you had to do major brass surgery to put anything inside the tender.  I kind of took the cheater's way out and bought one of the Rivarossie Big Six tenders and cut out the coal load so the receiver could be installed.  The loco is now DCC and still runs well.  If and when we ever get a new club space, I will probably put a sound module in it.  And yes, the original tender and water bottle are still in the box, still unpainted. 

[jbrock27]

Had 3 cups, thanks.

Thank you for that explanation and tutorial Joe.

[jonathan]

Well, that does explain the flash... and it didn't put me to sleep.    Thanks for that. If I read it correctly, the light will flash if the loco goes over a bit of dirty track, the motor briefly loses full current but keeps moving, providing the kickback.  It would be a very quick event.

Ebtnut, I have remotored the Q-4 as well.  Runs great, but won't be adding DCC.  I like your solution.

I've been slowed down a bit on the rebuild.  As I started to reassemble the drive train this morning, the middle driver (the blind one) froze up on me. I've figured out it's not a quartering or linkage problem.  Something's going on between the axle block and the wheel on the left side.  This make take a couple days to noodle out as I have to disassemble now painted parts--nerve racking indeed.

Regards,

Jonathan

[Irbricksceo]

Fascinating Joe thank you for your post

I remember your q4 post Jonathan, very nice looking loco. Was that the one w/ the screw reverse? Good luck finding the problem.

[ALCO0001]

Johnathan,
Nice work.
Was the Rustoleum paint high gloss ? I see your troubles with the decals that I had myself .I  ended up redoing them and put a top coat of clear over the baked paint and it solved the problem ,but before the clear I gave it a quick dunk in some vinegar to sort of etch the paint so the clear would stick AND rinse quickly or the brass will corrode.. It cost me a lot of time and a lesson in patience.Thanks for sharing !
Jack

[jonathan]

The final coat of paint was a high gloss, custom transparent black paint.  Perhaps I didn't get is thick enough for that perfectly smooth finish.  Ah well, I did a bit of weathering and it looks much better, at least, something I can live with and not strip and redo.

I soak the bare brass in vinegar for 24-hours to get the etch.  Never tried it after the loco had a primer coat, if I read you right.

Irbricks, the screw reverse was on the 0-10-0 U class switcher.  That baby runs like a dream.  Actually the Q-4 runs pretty well, too.

OK, Question time.

I'm 99.99% sure I accidently got some thread locker on the axle of the blind driver.  This worked its way between the axle and brass journal that sits in the wheel well if you get my meaning.  This froze the wheel of course.

I have removed the driver from the frame.  Using a pliers I can hold onto the brass journal and turn the wheel, but it's really stuck.  I have tried light oil and paint thinner, while turning the wheel.  This has made it a little easier to turn, but still no free enough.

So... is there a chemical, or process, I can use to get the thread locker from between the journal and axle?  I have considered applying heat, and or soaking in hot soapy water.  Just not sure what to try next.

I do have a gear puller and quarter.  As a last resort I will pull the wheel and clean it out manually, but that's scary stuff.

Thoughts?

Thanks in advance.  Hoping I haven't created a permanent varnish. 

Regards,

Jonathan

[GN.2-6-8-0]

Have you given any thought to soaking the driver and axle in say maybe alcohol over night? Only concern might be if its is a insulated driver's wouldn't want to chance damaging it.