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We are experiencing technical difficulties....

Posted:
Mon Apr 28, 2014 5:52 pm
by bkrownd
I added lots of wiring to distribute power to all areas of my 1 lane wood track. The track is modular in 3 panels, so in addition to the power supply in and controller connections, there are banana plug jumpers connecting from the central power area to the outer panels. It has lots of tight curves where I've had trouble getting the copper tape to stay down on this gritty paint job, so there are numerous power taps in the curves in case the tape gets kinked or cracked which would restrict power flow. There's no excuse for current not getting to any part of the track. 18 guage copper stranded everywhere.
So I fired it up, and it was not a complete success. 2 of the panels work normally. The third panel will not get clean power to the car anywhere. The cars "stutter" to varying degrees everywhere on this panel, and ONLY on this panel, often grinding to a halt. (it gets worse the slower the motor turns) I checked that there is no crossed connection from red to black anywhere. My multimeter shows no short, and without a car the voltage is fine. I tried disconnecting various parts of the power distribution on that panel. I tried connecting only directly from the controller to the copper tape near the car to eliminate any intervening bad connection. Same behavior every time. So, I'm left wondering if the network of power tap connections on the backside is somehow interacting with the power supply and motor in some weird way? Is this behavior familiar to anyone?
Re: We are experiencing technical difficulties....

Posted:
Mon Apr 28, 2014 6:41 pm
by bkrownd
That would indeed be a tricky one, but the cars are definitely on the braids with clearance below the guide keel. It wasn't a problem before I did the extra wiring, either.
Re: We are experiencing technical difficulties....

Posted:
Mon Apr 28, 2014 7:37 pm
by slothead
I have a 2 lane wood oval made from 6 sections with power taps that go to each section. Even though I took my time with the wiring, I still made mistakes that got some of the wires crossed, and had the same problem you have.
Somewhere you have the wires crossed so you're getting short circuits - the positive and negative leads are touching. I used RCA plugs and when I went back and checked that's where the errors were, at the solder joints in the plugs and jacks.
Retrace your wiring and you should be able to sort it out.
Slothead
Re: We are experiencing technical difficulties....

Posted:
Tue Apr 29, 2014 7:45 am
by RichD
If it was me and I was building a track of this sort it would be braided and no jumpers would be needed. It does indeed sound like you have one of your jumpers reversed.
Re: We are experiencing technical difficulties....

Posted:
Tue Apr 29, 2014 11:13 am
by bkrownd
There's no conductor path between red and black (short), unless there's some normally insulating material somewhere that's weakly conducting once more current starts flowing in the circuit to power the motor. The behavior is more like a weak contact, but I even tried applying the power directly from the contoller to the copper tape near the car.
Re: We are experiencing technical difficulties....

Posted:
Tue Apr 29, 2014 3:02 pm
by Florida_Slotter
Well there is always one way to find an electrical problem, especially one that you have induced.
Disconnect everything and make it the way it was prior to the changes.
Then insert one change at a time, test to make sure it still works.
Now, insert the next one and test again.
Repeat the above step until all changes are implemented.
Yes, it is a lot of work, but actually much quicker in the long run.
Just please do not ask me how I know this!
Re: We are experiencing technical difficulties....

Posted:
Tue Apr 29, 2014 5:18 pm
by bkrownd
These connections are all soldered. Damn the torpedoes, full speed ahead!
For now the best answer I have is turning up the voltage and powering through it until the next time I take things down... I only have a short window that the track is allowed to occupy the living room.
Re: We are experiencing technical difficulties....

Posted:
Sat May 03, 2014 6:39 pm
by bkrownd
I turned on the track for the first time since Monday, and all 3 panels are smooth today without making any changes. Even the same car that had the worst problem last weekend was at full power today. No idea why. The problem will probably come back at some point.
edit: nevermind, it only took about a couple hours for issues to start showing up again...
Re: We are experiencing technical difficulties....

Posted:
Sun May 04, 2014 7:29 am
by 2FER SLOTS
Checking voltage drop should find your issue.
Could be wires or the tape itself.
Re: We are experiencing technical difficulties....

Posted:
Sun May 04, 2014 2:05 pm
by bkrownd
It has to be a weak contact(s) somewhere. (Oscillation seems to be ruled out) Since the braid/tape is the only contact in the system that is physically changing as the problem comes and goes my latest idea is that somehow the tape on only that one panel may have been far more dirty/oily/oxidized than the other two. (originally an idea I rejected as too unlikely) That would explain why it has been getting better over time. I have a car running on autopilot at a slow speed so I can monitor for the problem to return, and have been cleaning the tape whenever/whereever it does which so far always helps in the short term. (if it's a combination of problems that's step 1 anyhow)
I will be looking for voltage variations when I locate an appropriate resistor. Eventually there will be defects in the tape between the power taps as the tape ages, and that will be something that I need to test occasionally in the long term.