track power issues

[hirailr64]

Train is running with no issues when it abruptly stopped.  ZW circuit breaker tripped.

ZW breaker reset, applied power to track and breaker tripped again.  I removed the locomotive and cars.  Applied power again and the ZW breaker tripped.  I removed the track leads at the transformer and tested for voltage at the transformer terminals.  At zero throttle, my meter read 6 volts.  Pushed the throttle to max and the meter read 21 volts.  I reconnected the transformer to the track, pushed the throttle up to max and read the voltage at the track.  Meter read 4 volts at the track just before the ZW breaker tripped again.  Cleaned the entire loop of track, checked for any metal that may on the track, spot checked continuity from center rail to outside rail.  Meter read very close to zero.  I did all of the previous checks again.  Same thing.  I am completely stumped.  Any help would be appreciated.

Thanks.

[ADCX Rob]

You have a defective track piece - insulation failed.

Remove track in sections or individually and try again until the issue goes away. The last piece you removed is the problem one - inspect carefully for breaches in the insulation.

[lionelsoni]

A binary search may be the least disruptive way to find the short circuit.  This method is simply to divide the entire track into two sections, then test those halves separately.  Then repeat the search on whichever one still has a short circuit, and so on.  This can avoid a lot of disruption, especially if a lot of track is involved.

It's too late to be of any help to you, but a good practice on a layout is to divide the track into sections from the start, even if they will all be connected together when in use.  What I do instead is to solder the individual rails together, with the track pins removed.  This has the benefit of easy removal of a small piece of track for repair or redesign (like putting a turnout in place of a straight piece), and provides a better electrical connection than the track pins.

[hirailr64]

Thanks I will giv a try.

[sir james I]

IF the track is not screwed down. Disconnect all the track from the lockon section. Add one section or just a few till the breaker pops. Then you have narrowed it down to that section. I did not change the font. Software here sucks.

[hirailr64]

[quote user="ADCX Rob"]

You have a defective track piece - insulation failed.

Remove track in sections or individually and try again until the issue goes away. The last piece you removed is the problem one - inspect carefully for breaches in the insulation.

 

I took three 10” sections apart and tested each section connected to transformer power set at 15 volts.  Two of the three showed 15 volts.  The third only showed 3 volts.  I am thinking this the source of the failure??

[teledoc]

BINGO!! That would be the problem piece.  

[ADCX Rob]

hirailr64

...The third only showed 3 volts.  I am thinking this the source of the failure??

You bet! Check the insulation pieces on the center rail for a fault or breach allowing the rail to touch the tie.

You can replace that insulation with a new piece of fishpaper... the track is still good.

[hirailr64]

Replaced three sections of track with a 30" section for safety sake.  Hooked up a small transformer via Alligator clips and set a loco on the tracks.  Everything worked.  Hooked up the main buss wiring to my ZW and turned up the throttle-no breaker trip.  Set a loco on the track and turned up the ZW.  Loco ran for 5 minutes then stopped and the ZW breaker tripped.  Removed loco and noted that the loco was hot.  With nothing on the tracks, I turned up the ZW throttle and the breaker tripped again.  My next look will be all of the buss wiring.  ?????

[TrainLarry]

Recheck all your wiring for a short. Disconnect 1 set of wires at a time and apply power. If the breaker trips, that wire is good. Remove the next set and apply power. Do the same until the breaker does not trip. The last set of wires then is bad.

 

Larry