I have just added power distrcts to my layout and have noticed that when 2 locomotives get into this one district I get a faint light come one in my CP6 and the engines slow down. When one train leaves the district the other runs fine and light goes out. Only happens in the one distrct. I have cleaned the track and wheels on locos. I have as much voltage in this district as there is in all others. Polarity not a problem. I do have turnouts in this district but am not shorting on them. Any suggestions. There was no problems before I created the districts.
That’s the downside of using a light bulb as a current limiter. They aren’t all or nothing. The fact that the light glows faintly means you are drawing enough current in that section to almost light up the bulb, which is using up some of the voltage causing a drop, which slows the locos.
If it only happens in that one section, you may have too long or too thin a wire running to that section. Or inadequate feeders. This will cause a voltage drop which increases the current draw to closer to the light bulb’s threshold.
I am using all 6 districts on the cp6. I could reduce this if I need to. My bus wires are 14 gauge, and feeders 18. I have a maximum run of 10-12 feet from district back to cp6 unit.
John, there is no reason not to use all 6 power districts on the CP6. The reason that I asked about how many were in use was to suggest that if you had an unused one you could move over the two wires to a different terminal on the CP6. That would at determine if the CP6 was at fault. That said, you could swap wires on two of the power districts including the one causing the problem and see what happens.
The 14 gauge bus wires certainly seem adequate as do the 18 gauge feeders. It seems to me that a maximum run of 10 to 12 feet from the farthest power district back to the CP6 is not unduly long. So, I don’t see the size or the length of the wiring as a problem.
the bulbs are beginning to glow because there is a larger amount of current flowing than expected. Too small wire gauge or too long wire will add resistance, reducing the amount of current causing the locomotives to slow but not additional current causing the bulbs to glow.
could there be a low level short in that district that is already drawing some current? This can be checked with an ammeter when nothing else is drawing current (e.g. non-running locos with active sound decoders, track powered lamps, …).
could it be that the locos are drawing more current because of a grade?
My voltage when no loco on track is 10.4. This is constant over the whole layout. When I run one loco on the district that is in question volts read 9.8 not much of a draw or is it? 2 locos on same district volts go to 8.7 with some fluxuation up to 9. Both locos run slow till one leaves that district, then both go back to set speed. And of course with both loco in district cp6 light comes on. As I said before, all other districts are fine.
That seems abnormally low - what sort of meter are you using? Normal HO track voltage is 14-15V. Systems with variable scale settings use 12-13V for N scale, and 18 or so for O scale. Even a not-exactly-suitable for DCC meter shouldn’t read that far off.
The size of the bus and feeders seems fine - and not too long. However, in a given district, how many feeders do you have? ANd at the borders of each power disctrict, do you have gaps in BOTH rails?
Your voltage is very low. Look at increasing wire size and/or adding feeders. Several years ago when I was running voltage drop tests for NTRAK, voltage would drop from 11.8 volts at the booster to below 9 volts after about 75 feet of 12 ga wire. That’s a one way distance with a 3 amp load.
You should compare the readings to readings on the other districts. I would also try jumping the JP6 for that district to see if there is any improvement.
At this point, if it were me, I would flip the wiring between the problem district and another district to see if results improve or does the problem simply move to another power district connection on the CP6.
Once I did that, I would add at least one pair of feeders to the problem power district. The voltage drop seems indicative of too few feeders, a problem that I have experienced on my layout in the past.
The OP’s observation about the voltage drop when the second loco entered the power district should have nothing to do with current draw unless he meant that he was measuring amps as well as volts. What he is describing is voltage drop due to a wiring issue.