I'm starting to buy electronics for my layout. It seems like everything I look at recommends using a dedicated power supply, (stationary decoders, signal systems, command station, block detectors, boosters, lights & accessories) Is there a better solution than having umpteen wall worts to power all these devices? Does anyone build a multi-output power supply tailored to model railroads (like computer power supplies)? What are you using to power your systems? I really appreciate the input. Greg
Things wanting power look for several details: voltage amps "noise" AC, DC, or not caring Myself, I would look to partition the devices by needs and tolerances - certainly one wall wart per stationary decoder is excessive! DCC command station tends to be electrically noisy (and DCC bus doesn't always tolerate other sources of noise well), so I'd give that it's own power supply. One transformer per booster / DC controller (is important, as trying to share transformers can cause short circuits and smoke and flames and bad things ) Then one circuit for lights (so you can turn them on and off independently), and one circuit for accessory decoders / block detectors / signalling. Effectively an Accessory Bus running parallel (but not too close, else it will pick up noise) to the track bus. Picking a voltage and amperage that will suit all the accessories; most accessories are in the 12-16V range, so a home-electrical / radio shack / similar store should have Bigger Wall Warts that provide enough volts and enough amps to make you happy If you have remote turnouts, consider a separate power supply, or some nice filtering for them, because solenoids throwing are also fairly noisy. In terms of commercial multiple transformer / multi-tap systems, I'm not going to be much use; I'm electrically inclined and across several oceans, so I build most of what I need myself. (If you doubt your skills on wiring and insulating, get someone else to do it - 110V or 240V is not forgiving at all) My gut feel would be that anything targetting models specifically would be somewhat pricy, compared to a home-electrical store So, you could reduce it to several, higher amperage, power supplies: command station + first booster lighting turnouts all other accessories second booster, if you have a Big Layout, or a Basement Finally, Welcome to TrainBoard
Hey Greg. Check out a company in PA called dccdevices.com .they have a system to run all you have mentioned and you only need 1 power suplly for it .It has 20 channels to hook everything to and expandable to over 100 by adding more units and the great thing is you run it from your controler .All you want in your hand at any time .I saw this system and the man that designed it back the begining of january and man this thing does everything very easy .I have a NCE system I am upgrading and then will get this system .They have downloads for all the DCC systems so you can see what you can do and how easy it is .You cant go wrong with 2 wires .Cant get any easier than that .Have Fun . Marty .
Thanks for the responses. While browsing Home Depot I found a power distribution module made by Leviton. Its a 12VDC 1500 ma 6 output distribution module that comes with its own wall wort. http://www.leviton.com/OA_HTML/ibeCCtpItmDspRte.jsp?item=41304§ion=10356&beginIndex=0 I'd like to run several Digitrax DS 64's (switch controller), BD16's (occupancy detector), & SE8C's (signal controller) each will accept max 300 ma of power. I'm trying to figure out if this leviton model supplys amperage equally accross each output, or if it is supplied just to the outputs in use. (I wrote leviton an email). Also, is it important to have different systems (track, switch machines, occupancy, lighting) on their own power supply? I'd like to have track on one, and everything else on another. Marty, that controller looks interesting, but I think I'll need something that has inputs to generate feedback (like switch position, status of signals). Take Care, Greg
Looking at the specs of that Leviton box, 33.5W over 13Vdc gives me about 2.58A, so I'm guessing it's 1.5A total, not 1.5A each. Not to mention the 12V input doesn't look big enough for 9A input. Beyond "each booster on a separate supply", you can common them all you want; as long as they agree on voltage required. Obviously if one accessory demands 20V and the second demands 7, they're not going to be happy sharing a 12V supply. The only other reason to separate things might be noise - if you find your block occupancy system get upset (trains appear / disappear, for exampe) every time you throw a point, for example, then they may want to be split up. Thankfully, that decision is one you can make later - buy just one supply now to save money and see how far it stretches Last point is that (I've found) the "Wall-wart" form-factor (little box that plugs into the wall) tends not to get into serious amperage, and if you want 5A or more, you may need to get a "stand-alone" boxed power supply, with a mains cable on one side to plug into the wall, and a low voltage cable / cables on the other side. Thinking Radio Shack, if you still have them, or similar.
Thanks ATSF Admirer, In the begining I figured small electronics should come easy, after all I've wired whole houses. But house wiring is just running cable and plug and play to outlets, switches and lamps. When I get down to the small electronics level, it seems like it needs to be alot more exacting. Or else I'll burn up all my expensive circuit boards. I figured that Leviton model is 1.5a total, now what I need to figure out is how 1.5a is divided among its six outputs. For example each output supplies 250ma regardless if it is loaded or not, or is the 1.5a divided only to the outputs that are carrying a load. I've wrote Leviton to ask them. I guess my biggest problem with alot of wall worts is primarily weight and secondarily space (on the power strip). I'm building a small portable layout (28x80), but want lots of swithces and signaling that will eventually interface with a laptop. For the portability factor, overall weight has become an issue. Thanks again. Greg
That Leviton is a pretty tiddly little box really. I can't see you needing much in the way of boosters on a layout that size, so as AATSFA says you probably only need one supply. Personally I'd have a separate supply from my DCC for lights and accessories, and if the DCC was fairly well loaded (more than 2-3 A) I'd probably split the signalling and stuff off to a third one. But I'd also put them all in a box together with a single mains feed, much as I have with the two supplies I currently use (one AC for the DCC, one bipolar DC for my Tortoise switch machines). I've not heard anyone complain on here of this being a problem, but one thing with wall-warts is that you are making the low voltage wiring longer which will increase volt drop. Having the power supply close to the point of use is better.
Thanks Mike, Thats an interesting point about voltage drop. I asked Leviton about how their power distribution module works and the response I got was: Our 1x6 is 1500 milliamps total. This means if 1 port takes 1 amp, you only have 500 milliamps left for the other 5 connections. This sounds like its just a paralell circuit. So I guess if I'm going to use something like this with these Digitrax products which accept max 300ma input, I'd need to make sure I either used enough devices to use all the power or put resistors in any unused branches to cook off any extra amperage. Greg
No. I thought you said this earlier in the thread, but passed it by as a grammatical unclarity Most power supply units (certainly those for the uses being discussed here) provide a fixed (or with little variation) voltage out. They also have a maximum current capacity they can supply. Devices using this supply will draw only the current they need. So if you have a 1.5 amp PSU and connect a DCC pulling 0.5A and some lights pulling 0.3A you are just using 0.8A of the PSU's capacity - it could supply another 0.7A if something needed it, but you certainly don't need or want to 'cook off' this amount. Of course, the DCC system will draw different amounts of current over time anyway. When you start a train ... more current, put the headlight on ... more current, stop a train ... less current, etc. So you can't actually fit a fixed resistor to do the cook off anyway. Now, I said 'most', so I ought to clarify that. What we have been talking about are 'constant voltage' supplies. There are things called 'constant current' supplies. These are commonly used to charge NiCd and NiMH batteries, but NOT lead-acid batteries. They push a constant current through the battery and use whatever voltage they need to do this. Obviously when the battery is flat the volts are low, as it gets full the volts rise. You absolutely do not want to use one of these on your trains - cook off resistors or not. OK, class dismissed :zip:
Thanks Mike, That's enlightening (Constant Voltage vs. Constant Current). I guess the Constant Voltage model you described was the only way I thought power supplies would work. But this Digitrax DS 64 got me a little befuddled, it recommends max 300ma input power. That just didn't make any sense to me, since I thought a device should draw only what it needed. And I haven't run across any other device that specify a maximum current. I asked Digitrax whether they meant that a DS 64 would draw 300ma, and they said no, that was the max that you should supply, but up to three 3 DS 64's could share the same power supply. So assumedly minimum 100ma maximum 300ma per device. This has had me in complete confusion about how I would regulate current, without having to make my own circuit, or buy a whole bunch of Digitrax PS12 (300ma) power supplies. I'm torn now between buying another switch controller, and just powering this one with the Leviton unit and seeing if it burns up.:wink2: Thanks again, Greg
For track power: I use a "kit" transformer that was packaged by Springhaven Shops here in Northern VA. That is where I purchased both of my Digitrax systems. Years ago, my first (Super Empire) and last year I purchased a Super Chief Radio. The kit transform is good for about 6 amps at 12 to 14 volts. Given that I will not be running more than 3 (max) 4 trains at ANY one time. (Two is more usual), it is plenty. For switches (Tortoise), I am using an old MRC pack set to 8 volts. For lighting I am using a Bachman Spectrum 2000 pack set to about 8 volts. For the few AC switch motors I have, I am using the same MRC pack w/ the AC terminals.
I am not sure what Digitrax mean other than you as the consumer of the product need to ensure that whatever you hook up to a DS64 will not cause the DS64 to draw more that 300ma of current. I run my DS64's directly off rail power supplied by a Digtrax Super Chief capable of a 5 amp output. Under normal conditions I would bet the DS64 would draw a somewhat less value than the 300ma it is rated for. I think your safe just keep the voltage at the same rating as the PS12.
Close.. What Digitrax means is that the power supply must be able to supply AT LEAST the current specified at the rated voltage. More current capability is OK, but keep the voltage within specified limits. If you power your DS64 from the track terminals, you are in effect powering it from a source capable of supplying up to 5 Amps (from your DCC booster), although the DS64 will draw only what it needs. Powering via AX1/AX2 or the Aux connector actually connects to the same places inside the DS64 (via isolation diodes), and only 300ma capability is needed, but if your Aux supply is rated higher, it's no problem.
Greg, that 300ma input limit is to protect the DS64 in the event that its output becomes overloaded. That limit just means that is what your supply should be fused at. All you have to do is put a 300ma or less fuse (or circuit breaker) between the power supply and the unit. That will limit the max that it can draw and you can use any amperage power supply that you have. You could supply five 300ma units with one 1500ma supply. just put a 300ma fuse in line with each DS64 with those being in parallel with each other.
Sorry I'm late - been away for a few days. I just had a quick look at the DS64 manual online and it looks like it simply needs a 300mA supply, connected in one of two ways, and then it says "The maximum input power for your DS64 is 300ma at 12V DC." That seems to me to just say that 300mA is the most it will take - it doesn't say anything about it has to be limited to that. One thing for sure is the instructions aren't clear. But at near $60 a throw I'd put a 20 cent fuse in line like Nelson says - it shouldn't do any harm
