Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Is SPST switch ok to isolate track booster?

2028 views
9 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Sunday, October 26, 2008 5:10 PM

 Actually that's probably good that it's different - that way it should lower the chances of someone accidently flipping it when they thought they were flipping a turnout.

                --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    January 2007
  • 180 posts
Posted by Otis on Sunday, October 26, 2008 3:53 PM

Just a post to thank you all, gentlemen, and Cacole in partic. for the complete instructions pasted above.  The booster is installed and wired up and working.

I decided to just use the big DPST switch I had bought that didn't match my panel, by putting it on the side of my control box rather than on top.  I put the PTB100 right up on top of the panel so the LEDs will remind me to throw the switch to isolate the booster  from the snap switch power line when I am running trains.

(Don't know why, but the company that makes the toggle switches that I used on my panel does not make a matching DPST . I could only find a much bigger one at a local hardware.)

 

  • Member since
    March 2007
  • From: Shakopee, MN
  • 225 posts
Posted by Weighmaster on Monday, October 20, 2008 3:58 PM

 Try using the SPST to power a 4PDT relay.  That would allow full isolation.  Gary

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Monday, October 20, 2008 3:32 PM

Otis,

I may have gotten the color codes mixed up in my earlier post when I was trying to remember them from installing a PTB-100 two months ago.  The old gray matter ain't what it used to be.

Here are the instructions provided by SoundTraxx, minus the diagram:

Properly installed, the PTB-100 will provide reliable programming of all Soundtraxx DCC decoders.  The SoundTraxx PTB-100 Programming Track Booster is designed to facilitate easy programming of Digital Sound Decoders, which have advanced technologies beyond what some command stations were intended to handle.  Most Command Stations were designed to program basic motor decoders and lack sufficient voltage and/or current to handle the needs of more advanced decoders, including most sound decoders.  The PTB-100 will raise the programming track output to a level adequate for programming without degrading the DCC signal.

Typically, the PTB-100 will be permanently installed between the Command Station and the programming track.  Be sure the programming track is electrically isolated frm the rest of the layout wiring.  Make your connections with the power supply and Command Station turned OFF.  There are just three pairs of connections to be made:

1.  Connect one BLACK wire to one output of your Command Station power supply.  Connect the other BLACK wire to the other output.  These are the same outputs as connect to the power inputs on your Command Station.  NOTE:  The maximum input voltage for the PTB-100 is 18 VAC or 22 VDC.  Minimum input voltage for reliable operation is 12 VAC or 14 VDC.  Optionally, you may purchase and use a dedicated power supply rated at 15 Volts DC, 500mA.

2.  Connect one of the ORANGE wires to one rail of the programming track (Do not connect to the main line!).  Connect the other ORANGE wire to the other rail.

3.  Connect one YELLOW wire to one Programming Track connection on your Command Station (these could be labeled 'Prog", 'Program Track' or something similar.)  Connect the other YELLOW wire to the remaining connection.

Once your PTB-100 is installed, you can begin to program your decoder just as you normally would.

The PTB-100 automatically connects power to the program track whenever a programming operation is started.  the GREEN LED indicates the status of the programming track.  A slow flash rate indicates that there is no power on the program track and locomotives may be safely placed on or removed from the programming track.

Once you initiate a programming cycle via the command station, the Green LED will change to a steady ON state, indicating that the program track is powered up and a programming operation is in progress.  Depending on the make of your command station, the Green light may remain on while your command station is in programming mode, or in other cases, stay on for only a few seconds and then revert to a flashing state after each individual programming command is completed.  In either case, locomotives should only be placed or removed from the program track when it is powered down as indicated by a flashing Green LED.

The YELLOW LED will flash briefly when an acknowledgment is received from the decoder and simply means that the decoder has programmed properly.  If the Yellow LED does not blink, re-check your decoder wiring.  Note: a motor or similar load must be connected to the decoder in order for the acknowledgment to be detected by the PTB-100.

The RED LED indicates a fault condition.  A slow blink indicates the PTB-100 has detected a short circuit across the programming track, most likely due to faulty decoder wiring in the locomotive.  When this occurs remove the locomotive and wait approximately 20 seconds for the PTB-100 to reset itself.  A rapidly blinking Red LED indicates the power supply voltage is too low.  Check that the power supply output voltage is at least 14 VDC or 12 VAC and replace or adjust as necessary.

  • Member since
    January 2007
  • 180 posts
Posted by Otis on Monday, October 20, 2008 1:01 PM
Thanks for the response, Cacole. I understand what you are saying. My concern as in earlier posts on the topic, was connecting the PTB to the same power source as the snapswitches. It is felt that the surges drawn by the snap switches will put the PTB in harm's way unless it is isolated by a switch or by using a completely different power source. I see now that the DPST switch I have will work. My programming track is always isolated as it is the end of a spur with its own programming feeders and separated by insulating joiners from the mainline. I just can't drive on to it. I push or put locos on it.
  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Monday, October 20, 2008 10:55 AM

There's no harm in leaving the PTB on all the time.  If you connect it properly to an isolated programming track and the command station's programming track terminals, the only time it will be active is during the actual programming process.

Don't connect it to the power booster, connect it to the programming track terminals on the back of your command station.  Those terminals do not have any power output until you enter the programming sequence.

If you connect the PTB to a power booster's output it will instantly go up in smoke.

If your programming track section is also part of a siding or main line that you will want to run a train on when not programming, you must use a DPDT toggle switch to change between "Programming" and "Operating" modes.

  • Member since
    January 2007
  • 180 posts
Posted by Otis on Monday, October 20, 2008 10:29 AM

Thanks, gentlemen.  That was what I suspected.

I was just trying to avoid cutting another hole in my control panel to accommodate a new switch---but here goes!

I don't need the DPDT, however, since the power comes through feeders from the power line to the switches.  They are always going to be "live" regardless of the position of the switch to the PTB100.  A DPST will do, and that is the only thing the local hardware has anyway.

And I have my section of programming track isolated with plastic joiners.

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Monday, October 20, 2008 7:59 AM

Since he's talking about the input power supply to the PTD-100, it's alittle different. Still, I would use a double pole switch to turn off both power leads. There SHOULDN'T be any way for the program track and the coils of the switch machines to interact, ie, no way for there to be an electrical connection between them, however just to be safe it's best to disconnect both. What size switch do you have? The DPDT version in the same form factor (heavy duty, miniature, subminiature) is usually about the same size, DPDT is your best bet with the center goign to the power supply and one side feeding the snap switches and the other feeding the PTB-100.

                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    October 2005
  • 1,047 posts
Posted by betamax on Monday, October 20, 2008 5:14 AM
You should use a 4 pole double throw switch to isolate the programming track, and a short section of track between the programming track and the rest of the world. You want to completely isolate the outputs from each other. As well, a dead section of track will prevent disaster when a locomotive creeps past the gap during programming. The last thing you want is track power appearing on the programming track during programming. A 4PDT will allow you to route track power to everything, and when you switch it to programming mode, it will disconnect the booster, route signals from the PTB100 to the program track, and kill a section separating the PTB100's track section from the rest of the layout fed by the booster(s). You can use a pair of DPDT switches, but the safer thing is a 4P version. There is info on this on the DCCWiki, but the site has been broken for a few weeks. That doesn't seem to be changing quickly either.
  • Member since
    January 2007
  • 180 posts
Is SPST switch ok to isolate track booster?
Posted by Otis on Sunday, October 19, 2008 11:48 PM

Awk, it's me again with a ques. re the Soundtrax PTB100 booster I am going to hook up.

I don't have another convenient power supply for the booster so I am still thinking of using a feed off the supply to the snap switches. 

This is what I was thinking: I have already an unused SPST toggle switch installed on my control board that is in a great spot to isolate the PTB100 if I use the power supply I also use for the snap switches.  Trouble is, it is SPST and I can't find a DPST that fits.

So the best I could do, would be a switch in one of the power lines to the booster board, not to both that a DPST would give. 

I am no expert, so I would like to know if just breaking the current in  the one line in this way is still safe for those times when I switch off the programming track and am using the snap switches?  Would there still be some danger from the unswitched line to the PTB100 board even though the circuit was not closed.

Thanks.

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!