Wiring a Circuitron DT-1 to a DCC system


Eric Zimmerman
 

I am trying to connect a DT-1 Detector unit to cause my DC powered crossing flashers.  The instructions do to offer a clear path foe using with DCC.  Any help is greatly appreciated.  I want flashers to operate bi-directionally.
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RicZ


nnjstevenstrong@...
 

Hello, James Armstrong here at nnjstevestrong@...
 
I have a problem:  one of my tracks has a small gap in one of the rails. The engine simply comes to a  stop  And I am notvery good at soldering.  Topull up the entire
 
track would mean a lot of soldering and rewiring under neath the table.  Which is the best way to go./  Would dropping a small amount  of solder be the best way?



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Don Weigt
 

Soldering across any gap is difficult. Solder likes to have a continuous support, so for best results with a rigid connection, lay a wire across the gap and solder it to the rails on either side. If easily installed, a rail joiner is ideal.

Rigid joints may cause problems with changing seasons, as typical wood layout bases expand and contract at a different rate than metal rails as temperature and humidity change. For a flexible joint, a U shaped wire can be soldered across. If the space below is clear and accessible, the wire can dive out of sight between the two holes in the roadbed where it comes up next to the rails. Or, you can follow the recommended practice of having a feeder from the track power bus to every piece of rail.

I've had good luck soldering rail joiners to both pieces of rail, but leave an unsoldered joiner every 10 feet (3 meters) or so as an expansion joint, adding one or more feeders to each soldered together length of track. But, I worked in electronics for 45 years, and am a proficient solderer.

Nickel silver rail is one of the easier metals to solder, by the way. But, make sure it's clean. Solder doesn't stick to paint, glue, or ballast... It's best to solder all the wires and joints before adding those scenic elements.

I think rigid track is also less of a problem when it's going around a curve. A long straight track has nowhere to yield, making expansion joints more necessary.

Don Weigt
Connecticut

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Don Weigt
Connecticut


John Myers <myersjohn7373@...>
 

I spend many fruitful hours watching my track expand and contract:)


On Sat, Jun 26, 2021, 6:13 AM Don Weigt <dweigt47@...> wrote:
Soldering across any gap is difficult. Solder likes to have a continuous support, so for best results with a rigid connection, lay a wire across the gap and solder it to the rails on either side. If easily installed, a rail joiner is ideal.

Rigid joints may cause problems with changing seasons, as typical wood layout bases expand and contract at a different rate than metal rails as temperature and humidity change. For a flexible joint, a U shaped wire can be soldered across. If the space below is clear and accessible, the wire can dive out of sight between the two holes in the roadbed where it comes up next to the rails. Or, you can follow the recommended practice of having a feeder from the track power bus to every piece of rail.

I've had good luck soldering rail joiners to both pieces of rail, but leave an unsoldered joiner every 10 feet (3 meters) or so as an expansion joint, adding one or more feeders to each soldered together length of track. But, I worked in electronics for 45 years, and am a proficient solderer.

Nickel silver rail is one of the easier metals to solder, by the way. But, make sure it's clean. Solder doesn't stick to paint, glue, or ballast... It's best to solder all the wires and joints before adding those scenic elements.

I think rigid track is also less of a problem when it's going around a curve. A long straight track has nowhere to yield, making expansion joints more necessary.

Don Weigt
Connecticut

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Don Weigt
Connecticut


Eric Zimmerman
 

What happened to my original question? This has gotten way off topic in a hurry.

Eric "Ric" Zimmerman


Puckdropper
 

I've found a fiberglass scratch brush is great for cleaning the rail before soldering. It takes paint and scenery materials off quickly without damaging the ties like a Dremel tool can. I'll often use it on new track as well as old to clean off any oxidation that's occurred.

A good no-clean also Flux helps a lot. If it takes more than 2 seconds to solder a feeder, you'll probably be melting ties.

One more tip: wipe that iron tip on wet paper towel or a sponge just before you apply it to the joint.

Puckdropper


Don Vollrath
 

Eric/Ric … what do you expect the DT-1 to do on a DCC system? Just get operating power from the track? (Add an external full wave rectifier between DCC power and the DC input to the board) You still need to utilize the IR sensors and output drivers as intended with DC systems. The DR-1 can’t do anything else.

DonV


Don Weigt
 

Eric/Ric,

If what Don wrote is true, that all you can do is power it from the DCC system, then I'd say, don't do it, unless you have a great surplus of DCC power. DCC power is relatively expensive, given it's from AC, converted to DC, then converted into DCC. It's expensive to add another booster if you load your track power down too much with stationary devices.

That external full wave rectifier DonV mentions should be one made for higher frequencies. Typical ones are made to be efficient at power line frequencies. DCC is primarily about 100 times that frequency and have components quite a bit higher. Common power rectifiers aren't very efficient at those higher frequencies: the diodes turn on and off too slowly, and leak power across from one DCC wire to the other that never makes it to the DC load.

Also, even though DCC is much higher frequency than power line AC, the voltage still goes to zero momentarily as it reverses polarity. Any DC device powered by it will need some energy storage in a capacitor on its input. If there isn't one built into the circuit board, you might have to add one for the circuit to work properly.

It would be better to run a DC bus around your layout if you're going to have multiple DT-1s, building lights, and so on to power. It would be very easy to run a length of "speaker wire" from any DC source on your layout to the DT-1.


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Don Weigt
Connecticut