Hey gang, no kidding, about 3 months ago I was thinking " Could there be a capacitor or something in decoders that stores and puts out voltage to motor when an abrupt zero-voltage is seen by motor whilst in motion, to keep loco rolling when hitting dead spots in rails ? " Well, apparently it now exists !..Now that I/we've bought several new DCC locos without it does anyone know what adding this feature to the decoders will entail both wiring-wize and cost ? I'm guessing $30.00 per loco and hard wiring to decoder having had to also remove loco's shells. Also, how will this fair with 'panic-button' on the throttle if (scenario>) we spot extreme danger up ahead and need to IMMEDITATELY stop train ? Won't train possibly keep rolling into the crash-site due to 'stay alive'? Don't get me wrong. I think stay-alive will be a welcome addition to the hobby as gapped (insulated/problematic) frogs will no longer be an issue and thus switches will only need an in-active ground throw and small, dirty rail areas will no longer be a threat..It's installing them that scares me..Yeah,OK, let the local train store do it. You know what that will cost, to boot..
TCS has a Stay Alive unit in HO that will aslo work in tenders in N scale. They are also developing one for N scale too!
The capacitor would be before the throttle control and would not discharge unless connected. Except for making those little glitches go away it wouldn't be noticed.
Lenz has had two different size units for a couple of years. They call it "Uninterruptable Signal Processing" (USP). ESU also has has a unit called a "power pack".
Stay Alive has been around for a while. Just learn to keep the track, wheels and pickups clean. Powered frogs also. This is one of the joys of model railroading. http://www.members.optusnet.com.au/mainnorth/alive.htm Rich
I'm pretty sure NCE now has a decoder or decoders that have this feature. Keep track etc are always helpful. Dave
Here's a You Tube video showing a Lenz gold series decoder with a USP module attached. Not only does the locomotive cross a 12" wide section of track covered with masking tape, it reverses direction while on the tape. I think there is enough capacitive coupling of the control signal to allow the decoder to respond to commands even though the wheels are insulated from the track. http://www.youtube.com/watch?v=2f2hmeNNCOs
Thanks for responces ..But I don't get it ! If 'stay alive ' is in the throttle as Shortround states above (or is it?), how could command to ' continue rolling ' be read by loco's decoder if track, being dead in a section, is unable to send this command into decoder due to being....dead..! ? I saw the video but how is this being accomplished across the taped track ? No one really addressed my question. How is 'stay alive' installed and how much does it cost ? Is it global in that one unit controls whole MRR ? Or does each loco recieve a unit ( which is what I believe it must be ) ? Again, how too will it affect panic button ?
I do not intend to cal BS here on you, but this I will have to see. The stay alive simply stores power so that the decoder can continue on the last command received. I doubt the decoder is receiving new commands. If a direction change is requested before the loco heads into a dead section it may look as if the decoder is responding as the momentum effect delays response.
The signal makes it through the tape because of the capacitive coupling of the signal through the tape. The signal would couple through dirty track the same way. The stay alive capacitor would provide the power necessary to cross a bad section of track and the capacitive coupling between the track and the locomotive pickup the signal allowing the locomotive to be controlled.
I will have to take your word on signal coupling. I am far from an electrical engineer, but just find it difficult to believe.
One of the basic properties of a capacitor is it's ability to pass an alternating current signal. The DCC signal is an alternating current signal. As long as there is enough capacitance between the track and the locomotive the signal will get through, in fact some of the power may actually be coupled across the bad connection. Dirty track and the tape on the track may represent an open circuit to a DC signal but not to an AC signal. This behavior is used quite often in electrical circuits where a capacitor is used to block DC or a low frequency AC while passing higher frequencies. If you find it difficult to believe that electrical signals can bridge across circuits that aren't connected look at the way a transformer works. The primary and secondary coils are insulated from on another and yet power is transferred from one to the other. Transformers use inductive coupling not capacitive coupling but you still have two isolated circuits that are passing electrical energy.
Oh, I think I see now..Tape represents gunk or schmutz on rails or dead switch-frog which normally could/would cause a stall out. At this moment stay alive comes into play ( immediate voltage or amperage drop,say ). So, what, SA acts as a capacitor,or what ? Or are you saying that although there is zero motor juice , SA responds to command within rail anyway..Yet how could even this be, in the case of a completely isolated/insulated cold frog ? And, again how much work and money is involved adding each SA ?
I am and Electrical Engineer, and while the signal will go across the tape via capacitive induction, power will not flow.
Stay-Alive is not an add-on technology that you add to an existing decoder installation. Instead, if you want Stay-Alive capability in a locomotive, you must completely remove the existing decoder and replace it with a Stay-Alive decoder. As for cost, if you go to the TCS web site, you will find that their "Keep-Alive" decoders cost $20-25 more than their regular, non-"Keep-Alive" decoders. I have not looked at prices from other decoder makers. - Jeff
This is not true. The Lenz gold series and ESU version 4 decoders have the stay alive circuits sold as add-on modules.
Thanks! I was not aware of those. I see that the Lenz Power 1 module can be made to work with the QSI Titan U decoder as well as with the Lenz Gold Series for which it was designed. I wonder if anyone has adapted the Lenz Power 1 (~$44 street price) or Power 3 (~$60 street price) or the ESU PowerPack (~$50 street price) "stay-alive" modules to work with other non-Lenz/non-ESU decoders? An economical "stay-alive" module that could be added to low-cost decoders would get my attention. - Jeff
If you look at the ESU Lok Pilot version 4 manual on page 18 it shows how to make a stay alive circuit using a capacitor, diode and resistor. It's not the same as the circuit they use in their power pack but it should work. The power pack has a third connection not present in the simpler circuit. The Lenz modules also have three connections. The documentation labels the third connection as "charge" but does not give any technical details as to differences between the circuits.