Is it normal for parked locomotives to be drawing currant even when the lights are off? I recently finished wiring my 24" x 64" n scale layout and with no locomotives parked on it my NCE PowerCab system shows 0 amps. I normally have 8 - 12 locomotives parked in the yard and the system will fluctuate from about .40 - .60 with none of the units in operation. I have a double track parallel mainline on it and with a train running on one track there is a significant speed drop when I start running a second train. I believe the PowerCab is rated for 1.2 amps and with 12 units on the tracks I am not exceding that. Just wondering if maybe I have a problem in the wiring. I am using Kato unitrack and the first time I powered it up a couple of the turnouts were humming but the system was not resetting itself the way it would with a normal electrical short. I cun some power leads around the offending turnouts and now it runs fine. I am new to wiring anything DCC other than a simple table top loop of track with a couple sidings. My new design has a small yard and several multi turnout sidings. I hope I am making sense here, not much of a writer. Thank you for any suggestions.
Modeling the BN and CNW in N scale in the late 70's midwest.
Each decoder will draw a small amount of current. That's normal.
Really wiring for DCC is not different from wiring for DC. If you have a short, it's a short plain and simple. Voltage drop occurs on both. It's just more of an issue with DCC but drop should be avoided with DC as well.
If the layout passes the quarter test (short circuit test) and trains run all over. That's pretty much it.
Martin Myers
The NCE Power Cab provides 1.7 amps of power.
The most immediate solution to your problem would be to add one or more kill switches to shut off power to the yard itself or individual tracks within the yard.
You could also add more feeder wires to minimize or eliminate power losses that are causing your locomotives to slow down during normal operations.
A long term solution would be to add a "smart booster". The NCE SB5 would be an ideal addition to the Power Cab, and it would add 5 amps of power.
Rich
Alton Junction
davidmbedardNo....with non sound decoders with the lights off you layout should show almost NO draw.
I guess that depends on what you consider "almost" no draw. Every DCC loco on powered track will draw some current for the running processor. 8-12 locos drawing .4-.6 amps works out to about 50 miliamps per loco, which right off hand does sound high, but, depending on the decoders, it may be perfectly normal.
davidmbedardNope....I have 5 sound equipped....3 with caps...and a dozen non sound decoders on the layout and I sit at 0.2 amps...
Thank you for demonstrating my point - that DCC locos do draw some current when idle.
davidmbedard...and that's because of the caps....
No it's not, the caps only affect current draw for a very brief time at power up, once they are charged they do not cotinue to draw current.
oarb00...I am using Kato unitrack and the first time I powered it up a couple of the turnouts were humming but the system was not resetting itself the way it would with a normal electrical short...
I have heard of a few cases of Kato turnouts having a slight short from the coil to the track, causing them to hum.
Of course the decoder draws current. At least the microprocessor is running so the decoder is ready for the next operation. I measured the current some years ago but forgot the results. Was a few ma.
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
A useful experiment would be to take a current reading with all the rolling stock on the layout (as described). That would be that .4-.6 amp reading.
Pick up one locomotive at a time. Note the new current reading. The reading should evenly and gradually step down. If there's a big jump with a particular loco, think on that fact. If, when all the locos are removed, there's still a current draw, think on that fact.
Ed
Also any lighted cars - those will of course draw power any time the track power is on. Or a car with a working EOT device that isn't battery powered. If you have block detection and any cars with resistor wheels, those too will show as a load even when not moving. Decoders absolutely draw power even when not selected or moving. Even sound decoders with the sound muted. It's not much, but over a dozen ot so locos it starts to add up. The microcontroller int he decoder is always powered on, decoding DCC packets - how else will it know when you pick up the throttle and dial up that decoder's address if it isn't already listening? It ignores all DCC packets not addressede to it, but it has to listen and decoder those packets to see what the address is in case something comes along that IS addressed to it.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
This thread got my curiosity and I went into my trainroom and checked the amp meter when I turned it on. Wow, 1.2 amps with no locos running; but, I counted 24 locos on the tracks, about half (12) are sound equipped and there are at least 10 lighted passenger cars. I am running a Digitrax Zypher (2.5 amp). I have not been able to get all the sound locos to remain quiet when not being addressed, so I assume that is part of the problem, but I didn't realize that I was using almost half of the power supply amperage when all is at idle?
Just makes we more concerned about getting a booster.
-Bob
Life is what happens while you are making other plans!
It's the lighted cars that are killing you. Especially if they are not LEDs. 3x 30ma bulbs in each car, x10 cars, is 900ma right there - almost an amp.
Seems more to show how you don't need a booster - all that stuff and it's drawing less than half the system capacity. Now, about those people who think you need to buy then 8 or 10 amp booster because they have a dozen locos....
lighted cars will really increase your current draw. Especially if those cars are older incandescant lighting. Years ago for NTRAK we checked the current draw on one train with three Kato E8's and 9 lighted passenger cars. The locos had leds but the cars were incandescant. Current draw was just under 2 amps. a lot higher then most of us guessed before actually testing.
For what it is worth, probably not much, I have a two booster PH-Pro.
One booster, controlling the main lines and reversing sections, shows 0.50 amps for several standing locos, some sound, some non-sound.
The other booster, controlling the servicing facilities for both diesel and steam, shows 1.15 amps for a whole bunch of standing locos, some sound, some non-sound.
None of the locos on my layout are emitting any sound at power up.
rrinker It's the lighted cars that are killing you. Especially if they are not LEDs. 3x 30ma bulbs in each car, x10 cars, is 900ma right there - almost an amp. Seems more to show how you don't need a booster - all that stuff and it's drawing less than half the system capacity. Now, about those people who think you need to buy then 8 or 10 amp booster because they have a dozen locos.... --Randy
I just installed the LED strip lights (SMD's) in 5 of the Walthers cars, the rest have incandescent (mostly Spectrum and Rivarossi)bulbs. I plan to replace all lighting with LED strips. I will have to test the amp draw when I remove the culprits! Thanks for the info.
Thank you all for the responses to my thread, maybe a booster is what I need. I believe there are no shorts as the amp draw with nothing on the tracks is 0. I would not have thought I would need one as the layout is only 24" x 64" but I do run two trains simultaneously and also plan on adding a signal system. In the long term I plan on expanding to either side of this narrow section to create a horseshoe shaped layout so it would be a good investment.
The NCE SB5 would be the booster of choice for your situation, and it is affordable at around $165.
richhotrain The NCE SB5 would be the booster of choice for your situation, and it is affordable at around $165. Rich
Plus the SB5 will allow you to put ports around the layout to move the Power Cab without a loco shutting down.
Go to the NCE site. They usually have manuals on each product.
I have had the Power Cab for some years.
I replaced the incandescent bulbs in two more Spectrum passenger cars and the amp meter now shows just 1.0 amps. I have two more to go and they will all be LED powered!
I usually have 15-18 locomotives setting on the track. Some have incandancent bulbs in them. None of my passenger cars have lights in them. My power supply reads 0.7 amps with nothing running.
South Penn