Randy,
That LITTLE, and much, much more is accounted for with the driver/micro controller combination.
First, the motor driver -an LMD 18200- is controlled by the DCC signal. If my memory serves me well, the output is switched off when the signal is lost. Or perhaps driven to +15V and kept constant. If the trains are DC disabled this will be enough. If this is not the case, the micro controller can check the signal and switch off the power if it is lost for a certain period of time, say a millisecond.Furthermore, the LMD 18200 provide an over heating feedback and a current consumption feedback. Both can be examined by the microcontroller to shut down when necessary.
As mentioned earlier, a micro controller, a motor driver, an optocoupler and a few resistors, capacitors and diodes. Add your power supply to these 15 $ worth components and that is all what is needed for a booster.
I can send you a link with the details if you are intrested.
Walid
The Derby City Express NTRAK layout in 2008 was comprised of over 700 NTRAK modules using 1 DCS100 command station, 16 LNRP's, and 42 boosters. There was over 6000 feet of loconet cables in use. Digitrax figured out the LNRP's needed 14 volts instead of the initially designed 12 volts. All of those boosters and loconet worked well. With sound being the norm rather than a rarity now, more booster districts may be required for a layout that size.
There's a LITTLE more to it that just a micro and a motor driver, a booster should stop outputting if the input signal is lost plus you need short detection. If you don;t want to make your own consider the Tam Valley ones, they are cheap. And a simple design used to be on Hans DeLoof's web site. And I'm sure MERG has more than one.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
dehusman First off define segment.
First off define segment.
As clearly mentioned earlier, a segment is a part of the track electrically isolated from the rest and powered independently.
dehusman Do you need multiple boosters at $150 a pop or just a circuit breaker at $20 a pop?
Do you need multiple boosters at $150 a pop or just a circuit breaker at $20 a pop?
The only feedback from a booster to the command station would come over whatever data bus the system uses, ie Loconet for Digitrax. There's no two way comminucations over the input signal for the booster, it is strictly a simple input. If you daisy chained boosters to get the input drive to run hundreds of them, you could still hook up that control bus to get feedback. The command station doesn;t give a hoot about the status of any booster, it's up to each booster to cut power when a short is detected, or a circuit breaker installed between the booster and the track it controls.
And no need to modify it or filter it down to a 5V square wave, most boosters handle a wide range of input voltages - the boost is in the current, not the voltage. Since it's easy enough to build cables to use Brand X boosters with Brand Y command stations - I'll go out on a limb and say all mainstream boosters can handle 12+V on the input termina,s. so they can be fed directly fromt he track output of an upstream booster. No circuitry needed.
khier1-For a single isolated track segment the minimum number is one. My first question is: If I need more power, what is the maximum number of boosters can I connect to this segment?
One. If you need more power you get a BIGGER booster (more amps) not ANOTHER booster.
khier2-Now the total number of boosters in a layout will be the number estimated in 1 times the number of segments. My second question is: is there an upper limit for the total number of boosters?
First off define segment. Each block doesn't need a separate booster. You only need an additional booster when you need more power. A "segment" can be several hundred feet long and have multiple "blocks" in it. For example I have about 100 ft of run that is divided into five blocks, each of which has its own circuit breaker, but it all runs off ONE "booster" One of my friends has about 1000 feet of main track and only has 2 "boosters". To need more than a half dozen boosters you would need to be running a basketball court sized layout with multiple levels and 10 to 20 engines running in each segment.
Dave H. Painted side goes up. My website : wnbranch.com
gregc i didn't think there was any feedback. The command station provides a signal, polarity timing, that each booster must supply to the track.
i didn't think there was any feedback. The command station provides a signal, polarity timing, that each booster must supply to the track.
Regards
khierBut you can alternatively get the signal from the previous track section and reduce it to a 5V square wave via an optocoupler.
this results in a slight delay which will result in a short when wheels bridge the gaps between boosters that aren't driven by the same signal source.
khierIn this case the bus is not involved unless a feedback is desired.
greg - Philadelphia & Reading / Reading
The number of boosters will be limited by the amperage available from the house's service in the train room. Remember, there is such a thing as a circuit breaker.
rrinker Over the entire thing - by design and specifications, unlimited, however there is a hard limit set by the design of the command station which will vary depending on the output capacity on the bus that drives the boosters, like the fan out limits on an given gate IC.
Over the entire thing - by design and specifications, unlimited, however there is a hard limit set by the design of the command station which will vary depending on the output capacity on the bus that drives the boosters, like the fan out limits on an given gate IC.
khier Dear All, What is the maximum number of DCC boosters can be connected together for a single track segment? Is there a limit for the entire layout? If a layout consists of say 300 segment (isolated electrically of course), is there anything that prevents feeding each segment with a booster and using 300 boosters? To shorten the discussion: no, I do not intend to have 300 boosters connected. I used an extreme to emphasize the point. Regards Walid
Dear All,
What is the maximum number of DCC boosters can be connected together for a single track segment? Is there a limit for the entire layout? If a layout consists of say 300 segment (isolated electrically of course), is there anything that prevents feeding each segment with a booster and using 300 boosters? To shorten the discussion: no, I do not intend to have 300 boosters connected. I used an extreme to emphasize the point.
The only limiting factor is the amount of money you want to spend.
Logically, it offers no benefit to having multiple boosters, as each booster would supply much more current than its power district would need. A 5A booster would probably be 5X more than you need.
Most layouts would run comfortably with one 5A booster. The only reason to add additional boosters is to increase the amount power available when the demand exceeds the supply.
For any given isolated track segment, one and ONLY one booster. You cannot connect multiple boosters in parallel to get more current.
You CAN also drive the booster inputs frooomt he output of a dedicated booster (one not connected to any track, only to other boosters) so you could have as much of 10 amps of drive to the row of boosters. Assuming 100ma needed per booster, that's 100 boosters total. It may be less, maybe as low as 10ma per, then it would be 1000 boosters. And nothing really prevents you from going to another layer - say the command station drives 5x 10 amp boosters, none of which connect to the rails, but instead all drive other boosters. Now at 100ma per booster, you can have 500 total driving the rails.
Not sure why this is important, even the biggest layouts around haven't needed to resort to any special daisy chain arrangements to get enough power, including giant home layouts like Ken McCorry's, or huge convention hall filling NTrack and Free-Mo setups.
richhotrainRegarding question #2, as I previously replied, in theory there would be no upper limit to the total number of boosters assuming that the current draw at any one time does not exceed the household breaker that the boosters are connected to.
that would require quite a few active locomotives
doesn't a command station need to supply a relatively low-power signal to each and every booster? There is probably a limit to how many boosters the command station can support.
Ed, thanks for the reply.
The melted trucks are irrelevant to the question. This happens only during short circuits with inadequate protection.
khierMy first question is: If I need more power, what is the maximum number of boosters can I connect to this segment?
One.
Study this:
https://sites.google.com/site/markgurries/home/technical-discussions/boosters/choosing-the-right-booster
and look at the melted trucks.
https://dccwiki.com/Booster
In the above link there is this line:
Warning: Do not wire boosters in parallel. This will lead to melted plastic and fried boosters. You cannot simply wire them in parallel. You must connect separate sections of track (power districts) to separate boosters
khierMy second question is: is there an upper limit for the total number of boosters?
Theoretically, no.
Cheers! Ed
khier Let me explain it more detail: 1-For a single isolated track segment the minimum number is one. My first question is: If I need more power, what is the maximum number of boosters can I connect to this segment? 2-Now the total number of boosters in a layout will be the number estimated in 1 times the number of segments. My second question is: is there an upper limit for the total number of boosters?
Let me explain it more detail:
1-For a single isolated track segment the minimum number is one. My first question is: If I need more power, what is the maximum number of boosters can I connect to this segment?
2-Now the total number of boosters in a layout will be the number estimated in 1 times the number of segments. My second question is: is there an upper limit for the total number of boosters?
Regarding question #2, as I previously replied, in theory there would be no upper limit to the total number of boosters assuming that the current draw at any one time does not exceed the household breaker that the boosters are connected to.
Rich
Alton Junction
If the sections are track are electrically isolated from one another, then there would be no limit on the number of boosters as long as only one booster feeds power to a specific section of track.
On my layout, a 5 amp booster provides power to four power districts, each protected by its own circuit breaker, and a second 5 amp booster provides power to four reversing sections, each protected by its own A-R circuit breaker. None of the 8 power districts receive more than 5 amps of power. Had I chosen to do so, I could have powered each district with its own 5 amp booster.
you've got two questions together ..
for a SINGLE track segment I would assume one booster,
for multiple segments, one per segment
khierWhat is the maximum number of DCC boosters can be connected together for a single track segment? If a layout consists of say 300 segment (isolated electrically of course), is there anything that prevents feeding each segment with a booster and using 300 boosters?
If a layout consists of say 300 segment (isolated electrically of course), is there anything that prevents feeding each segment with a booster and using 300 boosters?