NCE PowerCab

[Dr. D]

My NCE PowerCab powered/controlled my six locomotives on a 4 x 8 layout with a couple loops, a siding, and a number of spurs. I added about 50% to the layout (but didn't add that much track), rewired everything with additional feeders, and now everything is running very sluggishly and rather slowly. What am I missing?

[peteski]

Well, since the last change was increasing the size of the layout, that is likely the culprit.

What do you mean by "sluggish"?  Slow response to speed commands maybe, or just slow top speed?

How many locos did you run on the smaller layout?

Take all but one loco (and any illuminated cars if you have them) of the track and run it solo to lower the electrical load.  Does it now behave as expected?

How many loco memory slots do you have configured on the Power Cab (that you can rotate through)?  even with six, that should not be a problem.

[Dr. D]

"sluggish": slow response to commands and slow top speed

I have six slots on the PowerCab and I ran six locomotives on the smaller layout.

The increase seems so small that I'm wondering if that is the culprit.

I had already tried what you suggested -- running each locomotive separately (with the others off the track), and they run slowly by themselves as well.

[jjb62556]

Might be time for a booster. Any of the locos have sound?

[Dr. D]

Two have sound.

If I wired it properly, shouldn't running one locomotive without sound (and no other locos on the layout at all) travel at a good speed?

[peteski]

If even single loco runs sluggish then no booster is needed (regardless of how large the layout is).  Pooster supplies only as much amperage as the loco neded. Also slow response would not be a symptom.  I wonder if the momentum was accidental configured in the decoders (it is easy to do on NCE).  With the loco you are controlling still on the track press the momentum button then select "0" to make sure no momentum is configured in the decoder.

Another thing to try is to reset the entire Power Cab unit.  Press PROG, then 5 then ENTER to scroll through the options until you get to the "RESET SYSTEM" screen and follow the prompts.

Power Cab's internal booster can supply 2A od power (or whatever lower amperage rating the wall wart has - mine is 1.35A). That is plenty to power at least 3 N scale locos with sound (and likely more).

If you have some spare track to make a circle, I would like to see you connect the PowerCab only to that track, then try running a single loco on it. That should pinpoint whether the problem is the layout wiring or the PowerCab itself.

[NDave]

First thing I would do is check how much current your layout is drawing from the Powercab as you operate one or more locos, and any accessories (switch motors) you might be powering from the Powercab.. You can easily do this by enabling the Powercab's ammeter function. According to Googles AI:

"To enable the ammeter on an NCE Power Cab, you need to access the Cab Parameters menu and change the "Show Track Current" setting to "Yes". Specifically, press the Program/Escape (PROG/ESC) button six times, then press ENTER. Next, press the "1" key to activate the ammeter, and then press PROG/ESC twice to return to the main screen. The ammeter display will temporarily replace the clock display."

I ave used this function many times to trouble shoot a locomotive, or measure current draw by my stall motor switch machines.

[Maletrain]

My guess is that the process of adding the track has resulted in a poor track power feed connection somewhere. 

The suggestion to try the Power Cab with a small, isolated circle of track is what I think you should do first, to see if the problem is with the Power Cab or its Power Cab Panel, or with your track wiring.

[GGNInNScale]

Hi
The NCE current monitoring is a good approach.  I leave it on all the time.  If you are drawing greater than 1Amp, the engines may slow a bit on the "far reaches of the layout".  The PowerCab is rated for 2Amps max.  I talked to the NCE guys a while back about the addition of an SB5 to provide more current to handle the static load from the extra engines.  When I ran a certain group of engines (6), and had 5 or 6 idling on the sidings and yard, the draw would be about 1.3-1.4Amps or so.  The high-draw engines would slow enough to notice even with feeders.
So, here is something you might check- break the track connection somewhere convenient.  Then, take a DVM and check the resistance of one rail across the break, then the other.  This should give you an indication of a high resistance in the rail(s).  You can try to find poor connections by testing across each rail joiner, but you really need a milliOhmmeter to do this type of measurement

[peteski]

Yes the Power Cab's internal booster can supply around 2A (and has internal breaker if the current exceeds that).  But the wall-wart power supply included with the Power Cab is rated for less than 2A (mine is only 1.3A), so the wall-wart will shut down before the Power Cab's breaker trips.

The weak link is the flat cable connecting the handheld unit to the PCP (Power Cab Panel).  Even though that special flat cable has heavier gauge wires than a standard telephone-type wire (like the curly cord included with the Power Cab for when it is operated as a Pro Cab throttle), it will drop appreciable voltage when supplying currents approaching 2A. The modular connectors on the cable ends are also not designed for such heavy continuous current, and you can even feel them get warm under 2A load.

But let me remind everybody here that Dr. D confirmed that the problem is still present even with a single locomotive running.  It will be interesting to see what the ammeter feature shows on the Power Cab while only single loco is present.  Dr. D did not mention any other types of accessories connected to the DCC output, or to the track. Ammeter should show around .01A when nothing is on the track. Not zero because the red LED on the PCP is connected to the DCC track output and it consumes around 10mA or 0.01A.

Hopefully Dr. D comes back with his findings, since he seemed interested in getting assistance in solving his problem.

[peteski]

You can try to find poor connections by testing across each rail joiner, but you really need a milliOhmmeter to do this type of measurement

Easy and best solution is to solder rail joiners or add feeders to all track segments which do not have soldered joiners at least one end.  That is the best recommend practice for reliable operation.