I am running DCC and am finding (like many others) that if my track is not meticulously clean I will get stalling of my engine. It is usually a very small spot and sometimes the engine can even coast over it. Assuming that the motor itself is still using DC power, rectified from the DCC 15V AC, it would seem that a capacitor across the motor leads might give enough juice to ride over small dirty spots and turnout frogs. (And maybe add in a bit of momentum effect.) Has anyone tried this? If so what kind of capacitor? I realize you could not use those blue polarized electrolytic capacitors that are so common because when you reversed your engine you would be applying reverse polarity to the capacitor resulting in an exploded capacitor. (I learned that in my early electronic kit building days!) I would be interested in hearing from anyone who knows more about this stuff than I do and has any ideas, pro or con, about this. Thanks ahead of time.
Jim in Costa Rica
Modeling freelance Northern California late 1930s
If you were to try this you would have to use a non-polarized (NPO) electrolytic capacitor. Getting a high enough Mfd rating to really do any good would mean that it is physically rather large, so space for it would be the biggest drawback.
If it was practical, I'm sure DCC dealers would have kits available by now.
cacole If you were to try this you would have to use a non-polarized (NPO) electrolytic capacitor. Getting a high enough Mfd rating to really do any good would mean that it is physically rather large, so space for it would be the biggest drawback. If it was practical, I'm sure DCC dealers would have kits available by now.
Hate to rain on your parade but you do not just throw caps at a DCC loco to solve running issues. Go look at the below link. This guy is also very active in some Yahoo DCC Groups, SoundTraxx, for one.
He shares actual results.
Everyone, store the link in Favorites and do some reading.
http://www.members.optusnet.com.au/mainnorth/alive.htm
Rich
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.
Non polarized will not work. These capacitors are more for speaker crossover networks.
SoundTraxx started using a 39 ufd non polarized cap for isolating DC from the decoder to the speaker. The cap passes AC.
My old command control system, RailCommand from CVP Products, recommended using plain old 0.1 uf capacitors across the motor leads. I've removed these as I've been converting to DCC. On one locomotive, the capacitor was not readily visible and I missed removing it when changing decoders. Once the loco increased to a normal operating speed the decoder blew. After asking around online, and checking with Digitrax technical support, the consensus was that the capacitor was the likely cause of the decoder failure.
Rob Spangler
The small capacitors ont he motor leads are for RF supression, yet none of my locos without them has ever interfered with the radio or tv. Bachmann is famound for includign them, and they interfere witht he high frequency drive and BEMF sensing of good DCC decoders, and should always be removed.
A keep-alive capacitor to keep the loco running is significantly larger and connects in a different way. However, it's not DCC makign the track dirty. Cleanign the track with any sort of oil or liquid other than somethign that evaoprates completely and quickly just invited dust to settle right back on the rails. Cleanign with abrasives is bad too, as you end up with pits and gooves in the rail that, you guessedit, collect dust. Clean wheels and clean pickup wipers are every bit as important as clean track. My current layout is in a spare bedroom, but my previous layotu was in an unfinished basement - I had bare cement floors and walls, and open floor joists above. In both cases, the only cleanign I've ever had to do is when painting the rails, I don;t even own a track clainign car at the moment, I cna;t justify the expense. It's been weeks since I last ran a rain, and it will run fine, no hesitations, if I go to the train room right now and fire up something. A good solid cleaning of the rails and ALL wheels - not just locos, but cars as well, should get things runnign fine. Use somethign a little aggressive - for the club layout we run acetone in a cleaning car - but this is a modular layout stored in trailers between shows, and half the issues with flickering headlights are caused by loose rail joiners on the connecting sections of track, not by the track being particualrly dirty.
If all else fails, you cna add the capcitors to a DCC decoder, but this will generally void the warranty on them. Lenz and the newest TCS decoders have a facility to connect a power source after the fact, via a plug inmodule, if you have room for it in your locos.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
TCS and Lenz Gold decoders can have a keep alive system. The Lenz keep alive is incredible. I have seen an HO diesel loco go over a 3 foot section of dead rail on speed step 1 without stalling. But like anything else Lenz. It takes gold to buy it.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
The demo videos of the TCS keep alive looks to be every bit as good as the Lenz, and I've been very satisified with the performance of TCS decoders - they are my standard motor only installs.
If dirty track is the problem, a CMX car may be a much better investment that installing capacitors.
It takes an iron man to play with a toy iron horse.
I use 24V, 1000ufd polarized capacitors on the TSU Soundtraxx chips to improve the keep alive. It works great. I think their stock size is 220ufd. Some require more work than others to improve.
I'll have to check out the TCS keep alive video, that is good news.
Richard
Check out the new TCS decoders with built-in Keep Alive circuitry. I just received an e-mail announcement from them today announcing their new decoder series.
Train Modeler I use 24V, 1000ufd polarized capacitors on the TSU Soundtraxx chips to improve the keep alive. It works great. I think their stock size is 220ufd. Some require more work than others to improve. I'll have to check out the TCS keep alive video, that is good news. Richard
The factory capacitor that come with Soundtraxx are not "keep alive" capacitors to the motor. They are only "keep alive" for the sound circuit. This prevents the sound from cycling through it's start-up sequence if a slight power interruption is experienced. It has nothing to do with keeping the motor running.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ