Hi Folks
A couple of simple questions for which I can find nothing using the seach engine or the Digitrax manuals.
I understand that a power district is a section of the layout powered by a seperate booster with the track double gapped at each end of the district.
I also understand that a power district can be split into several power sub-districts using a PM42.
The question is, do the power sub-districts need to be double gapped at each end?
Also, is a reversing section set up on a PM42 automatically a separate power district as regards short circuit detection?
Thanks in advance.
Ted
HI Ted,
I use a PM52 in just that fashion, three "channels" are double gapped at both ends with the fourth as a reverse section also double gapped at both ends. Think that if you only gapped one end, you would really be extending the length of the adjacent section.
Bruce
Each power district has to be double gapped at both ends. A PM42 section set up as a reverser is ONLY a reverser, for short protection you have to chain it to another section - peopel sometimes have wierd problems when tyign one section of a PM42 to another, yo umight want to consider feedering the output of a PM42 breaker section into an AR1 for a reverse loop.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks for the replies. It's pretty much as I thought, thankfully. I probably try to link the reversing section up though another sub-section of the PM42 and if it doesn’t work try an AR1 or similar.
Cheers, Ted
Ted,
It's the terminology that confuses. Sub-districts are the same as districts electrically. Double gap as a district.
Digitrax recommends not using one section of a PM 42 as a circuit breaker and another as an auto-reverser for the same sub-district. There were reports of unreliable operation when set up this way. It's better practice to have the auto-reverser on a different PM42 or use an AR1.
BTW, The above is Digitrax recommendation, there have been many reports that having having them on the same PM42 works.
Martin Myers
A further thought on the PM42. I mainly get short circuits from driving locos into turnouts when they are set against it. Everything shuts down and I’m unable to throw the turnout (which is operated through a DS64 stationary decoder) to the correct position easily. I planned to use the PM42 to create 3 sub-districts leaving one PM42 output for the control of turnouts. (It may be 2 sub-districts and one reversing loop – I don’t know yet).
Does the control of turnouts need a PM42 sub-district or should they be wired straight to the command station? Is this a waste of one of the PM42 outputs?
It's probably a waste of a PM42 section. And you quickly discovered why just using local track power is not a good thing for stationary decoders. The most common short is running a switch set against you, and if that same track power runs the switch motor - oops. I'd just run a power bus right fromt eh command station to the DS64's and save the PM42 section for another track power district.
My plan, when I get space to build bigger than my Zephyr can handle, is to use the Zephyr's 2.5 amps to run the stationary decoders for Tortoise motors, and leave the track to a 5 amp booster or two.