Need help with a Tortoise Switch Machine

[Joe Satnik]

Dear Jon,

Do you have voltage dropping (a.k.a. current limiting) resistors?  You would need 3, one in series with each uncommon LED wire.

As far as not lighting, these are possible causes:

1.) Bad connections.
2.) Switch not closed.
2.) Wrong polarity  (swap leads on power supply).
3.) Burned out LEDs from missing resistors. 

Hope this helps.

Sincerely,

Joe Satnik

[jonathan]

Again, I'm starting to get the big picture.  There is no current in the aux poles, they are merely switches.  Duh.

Thanks, again, Joe.  Just for a test I touched the common wire to 8 and the other wires to 1, taking advantage of the tortoise resistors.  The lights indeed lit up.  So...

I will indeed need resistors for whatever colors I wish to choose, plus a separate power source for the signal itself.  The 234, and 567 poles on the tortoise, will merely act as switches when the turnout is thrown.

In my ignorance, I was trying to connect directly to the aux poles, thinking there was power connected to them like poles 1 and 8.

Still learning...  for some reason, I'm slow on the uptake when it comes to 'current' events.  

Thanks for your patience.

Regards,

Jonathan

[jward]

not sure what the current rating of your led's are, but a good starting point would be a 1000 ohm resistor. you could probably get by with just one on the common lead of the signal. the purpose of having them on the individual leads of the led's is to adjust the brightness of each colour led individually ( by using different values of resistor for each led)........if you feel your signal is too dim with 1000 ohms, try decreasing the resistance until you are satisfied. consider the use of 820, 680, 560 or 470 ohms, but i don't recommend using any value less than 470 ohms. these values are based on a 12 volt power supply, and typical led current ratings of 10-20 milliamps......

[Joe Satnik]

If you only lit one at a time it might be OK to put a single resistor in the common leg.  It does take away your ability to adjust each LED's individual brightness, though. 

You might want to start with a little higher resistance,  4.7K Ohm for example, and work your way down. . 

[jonathan]

The signal's instructions recommend 680 ohm/.5 watt resistors for red and yellow, and a 330 ohm resistor on the green.  I was wondering if a single resistor on the common would work (680 ohm).  It's OK if the green is a little dim.  Thanks for the tip on that.

At this point, I've mounted the signal and added a few extra feet of wire to each lead, just to give me something to work with.  I have a 12v bus wire to power the signal when I'm ready.

Will get a resistor at my next trip to Radio Shack.  Was thinking of hard wiring the yellow light (so I'll know the signal is powered) and using the tortoise switches for red and green.

Will post a video of the signal and turnout when I get it working properly.

Thanks again!

Jonathan

[jward]

i wouldn't hard wire the yellow. you'll either have the red or green lit anyway so having the yellow also lit would be redundant, as well as unprototypical. with most signal types, there is never more than one light lit per head.....

btw, whose signals are you using?

[jonathan]

I picked up a Tomar, target signal at an LHS, for a good price.  Wanted to get one to learn with for now.

Eventually, I will be looking for the B&O-style CPLs (pricey).  Need to build some confidence before I dive in with both feet.  I have considered scratchbuilding some signals, but my skills aren't up to that level yet.

Regards,

Jonathan

[jward]

oregon rail supply makes kits for pennsy style signals. you can substitute b&o style heads as they use the same circuit boards. you'll probably save about half the cost if you build them yourself from kits.

[jonathan]

Many thanks, folks, for guiding through the electrical maze.  Here is the progress on my project to date. This is a 9" wide shelf, along my far wall, that is used for engine servicing and some industry.

When switch is thrown to main route, the light is green:





When the switch is thrown to the spur (divergent route), the light is red:





Here's my somewhat crude soldering job on the switch machine.  White is common wire to current, red wire is red light, green wire is green light, blue wire is the other side of the current.



This is what it all looks like before the wires are tucked up and the skirting is removed:



Hopefully, no one minded I put this in General Discussion.  Seemed like an all-scales kind of topic.

Thanks a million!

Jonathan

[jward]

that is a beautiful signal.
on a related note, were you aware that the p&le used this type of signal in places? b&o had trackage rights over the p&le from mckeesport, pa to west pittsburgh, pa and many of their trains used the p&le to avoid the sharp curves and steep grades on the b&o's own line. so your signal might not be so out of place after all.......

[jonathan]

Bonus!

Thanks, Jeff.

Regards,

Jonathan

[Jim Banner]

I started drawing you a circuit this morning, but then the power when off.  Only just now got it uploaded, but in the meantime, I see you have it all worked out.  I have posted the diagram anyway because it shows a second way of doing the job while leaving all the switch contacts free for other uses.



The left hand circuit shows essentially what you have.  The right hand circuit includes the cross-wired toggle switch to operate the Tortoise. This second circuit works by lighting up whichever LED is connected to the negative motor terminal.  Which motor terminal is negative depends on which way you set the turnout.  While I have shown equal 1k resistors, you could just as easily use 680 ohm and a 330 ohm resistors for balancing the colours.

Great photos.  You have the eyes of an artist.

regards,
Jim

[jonathan]

Thanks, Jim.  I must be an artist at heart.  I usually don't worry about prototype with scenery.  I just do what feels good.  I have been swinging more towards prototype-thinking as of late.

I was going to attempt to wire the lights per your second diagram.  I couldn't noodle out the polarity problem because all the lights in the signal share a common wire.  That led me to believe I couldn't change the polarity of the individual signal LEDs without changing the polarity on all the LEDs. Thus, I would have either 'lights on' or 'lights off' and couldn't select which LEDs to light.

Still learnin'

Regards,

Jonathan

[jward]

ironically, as this discussion was taking place i was installing tortoise motors on my layout. i realized that an atlasd twin is two dpdt switches with the contacts cross wired as per jim's diagram. no wiring of contacts together, as it's already been done internally.



the two contacts on the side are dc power in, the two sets of contacts on the top go to the tortoise. flip the switch up or down to throw the tortoise. wiring a tortoise is thus made as simple as wiring a traditional switch machine........