I have a Digitrax Zephyr to do my trains with. This works great with N scale, but it might be a problem when I start to use it with some of the S gauge trains I have been converting. 3 amps was nothing when someone first designed those things in the 1950s, so power consumption would definatly be an issue if I want to use more than 1 at a time
What I saw through the oscilloscope gave me an idea: What if I bought a large 12 volt DC transformer and rigged it up with transistors, so its like an amplified version of what comes out of the DCS51? I definatly know how diodes and transistors work, and how to set them up, but what I'm not sure about is how big of a possibility there is for it to malfunction and destroy a DCC decoder. All I can say is, the Soundtraxx decoder from my other post wasn't actually the first one I bought, and I don't want to replace it AGAIN. Look, that happened because of a stray wire touching the track, but it still blew up the decoder. I didn't expect it to be so delicate, and I don't want to blow up ANOTHER because of a similar risky project.
Tell me what you think and what could be possible issues with this idea. Oh, and if anybody knows exactly where I am supposed to buy a transistor or diode of that size, send me a link...
Sorry Digitrax, but if I succeed, you may notice a few differences in the number of customers buying your boosters...
From what I know about DCC, the ac voltage is always present on the tracks, at the same value. The command station sends "packets" of information to the decoders. When you figure out how to do this get back to us. I would also like to get more power from my Zephyr.
I am looking forward to hearing about the results of the experiment. It should be very interesting.
Ed
That's what boosters are for. Not sure why anyone would pay $700 for a Zephyr Command Station in the first place that is street priced around $170 -- but in any case, one doesn't add more command stations, one adds boosters when more amps are needed.
Boosters are street priced around $150 (no command station function), including this 8 Amp Digitrax boosterhttp://www.modeltrainstuff.com/Digitrax-DB200-LocoNet-Booster-8-Amp-p/dig-db200.htm
Boosters with less amperage can be purchased for even less.
If you decide to DIY, good luck. But note that only one or two fried sound decoders in the process of working out the bugs would go a long way toward paying for a commercial booster.
Layout Design GalleryLayout Design Special Interest Group
The DCC signal is not an AC sine wave. It is a digital bi-polar signal. Play with the sweep on your scope so you can see the wave form.
Tam Valley Depot has some nice 3 amp DCC boosters available that will work with any DCC system, and will not load down/distort the signal like I suspect will happen with your solution.
Another option is to buy some used Digitrax boosters on eBay. I picked up a used 5 amp booster with wall wart power supply for $50 plus shipping...
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
There are also DIY boosters such as the Locobooster oon Hans Deloof's site http://users.telenet.be/deloof/
It's not quite as simple as it seems to generate a solid DCC signal on the rails. It's more than just switching the output of a transformer. The drive circuit of a typical DCC booster is an H bridge using low resistance MOSFETs in an H brodge configuration, switching a split DC power supply (+ and - relative to a common) rail to rail, or nearly so. Care must be taken in the amplifier design and any additional filtering to make sure the square waves are as squared off as possible (very fast rise and fall times) and that there isn't any excessive ringing of the signal. You will see that even on the simple booster designs like the Deloof one or the Tam Valley ones, there's more that just a couple of transistors on there.
Also, $700 is the price of a whole system with all the bells and whistles. You do not need to go that far - your Zephyr is fully upgradeable, there is no reason to start over with a more powerful system, just add on what you need. After 14 years I'm STILl using my original Zephyr as the 'heart' of my system, I've added on a few throttles and a DB150 booster over the years and I doubt I have $700 in DCC gear even adding it all up.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I predict there will be smoke...
Mike Lehman
Urbana, IL
jrbernier Another option is to buy some used Digitrax boosters on eBay. I picked up a used 5 amp booster with wall wart power supply for $50 plus shipping... Jim
I picked up a nib DB150 for $135 off Ebay
LAX1DUDEWhat if I bought a large 12 volt DC transformer and rigged it up with transistors, so its like an amplified version of what comes out of the DCS51?
Sounds like you're interested in building a DCC booster.
From your scope, you saw that the DCC signal on the track, while changing polarity, is flat during each half cycle. So the first step would be to use your tranformer to build a regulated DC supply. Regulated will result in a flat output at at least 12V.
The next step is to modulate the output (toggle its polarity) exactly like the output of the DCS51. As Randy said, an H-bridge is commonly used to rapidly switch the output connections between the + and - side of the supply voltage. 4 MOSFETS are used. Only 2 would be enabled at a time either connecting the + to the A output and the - to the B output, or visa versa.
Some digital logic would be used to enable one pair MOSFETS or the other. That logic would presumably be driven by a DCC signal available from the DCC command station or DCS51.
I wouldn't be surprised if there isn't a slight delay between the command signal and power output becasue when multiple boosters are invoked, they must all be syncronized, otherwise there will be shorts when metal wheels span the gaps between one power district and another.
LAX1DUDETell me what you think
greg - Philadelphia & Reading / Reading
RR_Mel Generally power transformers are designed for 50 to 60 hertz, DCC operates at about 8K. I doubt if that would work.
I meant that I would use transistors to control the output of the transformer, not the input. Valid thought, though.
rrinkerIt's not quite as simple as it seems to generate a solid DCC signal on the rails. It's more than just switching the output of a transformer. The drive circuit of a typical DCC booster is an H bridge using low resistance MOSFETs in an H brodge configuration, switching a split DC power supply (+ and - relative to a common) rail to rail, or nearly so. Care must be taken in the amplifier design and any additional filtering to make sure the square waves are as squared off as possible (very fast rise and fall times) and that there isn't any excessive ringing of the signal.
I will definatly do some research on those possible problems. Thanks!
--Lax
PS. I MEANT $700 HYPERBOLICALLY!
almost half of the posts say it will cost less than this
Now, to help clarify some of the other comments people have sent me:
The reason I want to do this is so I can find an alternative to buying five 8 amp boosters and having to make sure there are only two trains in each power district.
I want to have one massive power supply that does everything. I know it's harder to detect shorts this way, but I don't have to worry about blocks being in phase and I will probably save a lot of money doing this instead of buying a bunch of these.
Thanks for al the help, though!
By the way, would this be something that should be submerged in mineral oil?
Mmmm - You don't want 5 - 8amp boosters .... you want one single 40 amp booster !?
You realize that if an engine derails on a turnout and shorts, you will be welding parts together, right ? 40 amps on the rails just might glow in the dark under full load !
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Mark R. Mmmm - You don't want 5 - 8amp boosters .... you want one single 40 amp booster !? You realize that if an engine derails on a turnout and shorts, you will be welding parts together, right ? 40 amps on the rails just might glow in the dark under full load ! Mark.
There are always DCC circuit breakers to keep that from happening. But enough of them for a 40-amp booster and you're headed back towards that $700, instead of away from it.
To the OP:
There are LOTS of layouts with multiple boosters. Don't you think that if a single, high-amp booster was more suitable for such layouts, that someone would already be producing one? Even the CVP ZoneMaster is only 7 amps continuous.
Mineral oil? A 5 amp booster doesn't run that hot with a fairly ordinary chunk of metal heat sink and no fan. Good H bridge chips are inexpesinve enough to not need to run them right on the ragged edge of capacity. Helps keep the signal clean, too.
All you need to expand power wise is a DB150 or a DB200, not a DCS100/200, which are command stations as well as boosters and cost more.
You also need to look at how all those amps will be carried to the respective districts. Going to need a ton (maybe literally) of wire to get it there without significant voltage drop. Maybe start with an arc welder and modify from there?
Stevert Mark R. Mmmm - You don't want 5 - 8amp boosters .... you want one single 40 amp booster !? You realize that if an engine derails on a turnout and shorts, you will be welding parts together, right ? 40 amps on the rails just might glow in the dark under full load ! Mark. There are always DCC circuit breakers to keep that from happening. But enough of them for a 40-amp booster and you're headed back towards that $700, instead of away from it. To the OP: There are LOTS of layouts with multiple boosters. Don't you think that if a single, high-amp booster was more suitable for such layouts, that someone would already be producing one? Even the CVP ZoneMaster is only 7 amps continuous.
From a well know DCC site ....
Each locomotive will use about 4 amps. I did some quick math and it will cost upwards of $400 to make something simple with just existing tech (DB200s). Making just a simple 15 or 20 amp booster with the ps2012 this would cost a fraction of that. My main problem here is the resistance of the rails, not the number of locos. I just need something that can make sure the rails don't need a power feeder every three feet. Remember: This is S gauge. I am using track and locomotives (with replaced motors) from the 1960s. Call me crazy, but this stuff is so cheap! It just doesn't have the greatest connection between track sections...
Thanks for all the suggestions, though!
Mark R.Stevert Mark R. Mmmm - You don't want 5 - 8amp boosters .... you want one single 40 amp booster !? You realize that if an engine derails on a turnout and shorts, you will be welding parts together, right ? 40 amps on the rails just might glow in the dark under full load ! Mark. There are always DCC circuit breakers to keep that from happening. But enough of them for a 40-amp booster and you're headed back towards that $700, instead of away from it. To the OP: There are LOTS of layouts with multiple boosters. Don't you think that if a single, high-amp booster was more suitable for such layouts, that someone would already be producing one? Even the CVP ZoneMaster is only 7 amps continuous. From a well know DCC site .... The boosters with higher current ratings are better: FALSE. An oversized booster will have too much available inrush current for smaller scales. Unless you have correctly set circuit protection, locomotive damage is possible. If you employ a power management device and divide the layout into power districts, with a lower current (for example, 4A) setting, this may make sense. Remember, high current boosters can deliver a lot of current into a short circuit, as much as 60A for a brief period of time. Which results in damage before a circuit breaker can react to it. Mark.
I never said I will be using 60 Amps.
It will be 15 or 20 at the most. Like I said, I need a booster that can conduct through rails with poor connections between them, not a booster that can run 30 locomotives in the same district
LAX1DUDE Mark R. Stevert Mark R. Mmmm - You don't want 5 - 8amp boosters .... you want one single 40 amp booster !? You realize that if an engine derails on a turnout and shorts, you will be welding parts together, right ? 40 amps on the rails just might glow in the dark under full load ! Mark. There are always DCC circuit breakers to keep that from happening. But enough of them for a 40-amp booster and you're headed back towards that $700, instead of away from it. To the OP: There are LOTS of layouts with multiple boosters. Don't you think that if a single, high-amp booster was more suitable for such layouts, that someone would already be producing one? Even the CVP ZoneMaster is only 7 amps continuous. From a well know DCC site .... The boosters with higher current ratings are better: FALSE. An oversized booster will have too much available inrush current for smaller scales. Unless you have correctly set circuit protection, locomotive damage is possible. If you employ a power management device and divide the layout into power districts, with a lower current (for example, 4A) setting, this may make sense. Remember, high current boosters can deliver a lot of current into a short circuit, as much as 60A for a brief period of time. Which results in damage before a circuit breaker can react to it. Mark. I never said I will be using 60 Amps. It will be 15 or 20 at the most. Like I said, I need a booster that can conduct through rails with poor connections between them, not a booster that can run 30 locomotives in the same district
Mark R. Stevert Mark R. Mmmm - You don't want 5 - 8amp boosters .... you want one single 40 amp booster !? You realize that if an engine derails on a turnout and shorts, you will be welding parts together, right ? 40 amps on the rails just might glow in the dark under full load ! Mark. There are always DCC circuit breakers to keep that from happening. But enough of them for a 40-amp booster and you're headed back towards that $700, instead of away from it. To the OP: There are LOTS of layouts with multiple boosters. Don't you think that if a single, high-amp booster was more suitable for such layouts, that someone would already be producing one? Even the CVP ZoneMaster is only 7 amps continuous. From a well know DCC site .... The boosters with higher current ratings are better: FALSE. An oversized booster will have too much available inrush current for smaller scales. Unless you have correctly set circuit protection, locomotive damage is possible. If you employ a power management device and divide the layout into power districts, with a lower current (for example, 4A) setting, this may make sense. Remember, high current boosters can deliver a lot of current into a short circuit, as much as 60A for a brief period of time. Which results in damage before a circuit breaker can react to it. Mark.
A 15 to 20 amp booster WILL deliver MUCH higher current (yes, 60 amps) when shorted. Damage WILL occur before the breaker trips. I've seen it happen with just an 8 amp booster ....
The simple but potentially very Bad "Bigger is Better" approuch to booster power determination.
LAX1DUDE I never said I will be using 60 Amps. It will be 15 or 20 at the most. Like I said, I need a booster that can conduct through rails with poor connections between them, not a booster that can run 30 locomotives in the same district
You are solving the wrong problem. You are FAR FAR better off dropping a feeder every 3 feet. On my last layout there was a maxiumum of six feet between track feeders.
The solution you're proposing is a recipe for disaster. Even at "ONLY " 15 amps on the rails, if these are the old "American Flyer" style motors that top off at 16 volts, you're talking 240 WATTS on the rails.
Seriously. This thing you're talking about? DON'T DO IT!
Disclaimer: This post may contain humor, sarcasm, and/or flatulence.
Michael Mornard
Bringing the North Woods to South Dakota!
Wow...
Yeah.. that might be an issue...
The thing, though, about those trains from the 1960s is that they were built to operate from up to 300 watts. Most have 2 trucks that pick up power. One for +, one for -. No trucks that pick up on both sides or two trucks both for the same pole.
The short you are talking about probably wouldn't melt something like this:
There are no wires connecting the wheels on the conducting side. It flows around the entire body of the truck, which has a wire connected to it at the top. I have been working with these, and some are almost impossible to short in the first place. Even a wrongly configured reversing loop couldn't do much damage. Only the modern trains pick up power from all trucks on all sides, meaning that there are many wires inside that could be melted if there is a short related to power pickups or a reversing loop...
I'll keep that in mind, though!
Thanks!
Bayfield Transfer RailwaySeriously. This thing you're talking about? DON'T DO IT!
Thanks for the encouragement
This is why I am replacing the motors with DC can motors. The original motors, well, A:complicated direction control, B:needs power-hungry inductor coil, C: runs on 16 volts.
I know this sounds like a recipe for disastee (screw auto correct), but I have talked with professionals and have done lots of research, and I'm confident in myself that I can make this work. Once you break out the super glue, there's no going back.
LAX1DUDE:
Keep us posted. Just make sure you're not using smoke signals!
Seriously, it would be interesting to hear how you make out.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Didn't that Nikola dude experiment with this? Actually he was a pioneer in RC boats!
https://en.wikipedia.org/wiki/Nikola_Tesla
https://en.wikipedia.org/wiki/Nikola_Tesla#/media/File:Nikola_Tesla,_with_his_equipment_Wellcome_M0014782.jpg
Nothing ventured, nothing gained...
If you're replacing the old motors with can motors, are they still really going to draw 4 amps each? Seems like that might be a stall current but not a continuous rating. I could swear that at one train show I went to, there was a layout running mostly remotored Flyer on DCC using ordinary HO decoders, which top out at 2 amps peak, 1.5 amps continuous.
It's not just voltage drop through those rail joints, it will also degrade the DCC signal. And the amps, other than the actual load, has nothing to do witht he voltage drop. If you have poor track joints and 16V measures only 12V at the far end with a 3 amp booster, replacing it with a 20 amp booster will NOT change a thing. Replacing it with a 20V output may raise the far end voltage to 16V, buit it will ALSO raise the nearby voltage to 20V. Also not wanted. The problem of poor track joints adding resistance cannot be solved by injecting more volts or having a supply capable of sourcing more amps.
The correct solution is to bypass the rail joints as the power carrying part of the circuit, either by sldering or installing jumper wires across each gap, and supplying adequate feeders around the layout. There is also better quality track than the original Flyer track, including flexible sections which will reduce the total number of rail joints. This is the way to solve the problem, plus multiple smaller boosters, NOT one monster. It may "work" and not melt anything, but it won't actually solve the problem, you'll have just as much voltage drop around the layout no matter how huge you make the booster. It's just not the way electricty works.
Pulls up lawn chair and popcorn. This should be interesting.
Rio Grande. The Action Road - Focus 1977-1983
Having a 15, 20, or 50 amp power supply will not fix bad track connections. You either need to fix the connections or put feeders to every section of track.
riogrande5761 Pulls up lawn chair and popcorn. This should be interesting.
And don't forget the fire extinguisher.