I plan to use a DCS-100 as the DCC 'brain' for my layout and I will use 4-5 DB-150s as boosters. I do not plan to use the DCS-100 as a booster. I would like to know what the power supply requirements are for a DCS-100 when not used as a booster?
I have a spare 12v power supply that is rated 12v @4.2 amps. I assume that would be sufficient?
Thanks.
Modeling an HO gauge freelance version of the Union Pacific Oregon Short Line and the Utah Railway around 1957 in a world where Pirates from the Great Salt Lake founded Ogden, UT.
- Photo album of layout construction -
Without using the booster section I would think that power supply would be more than sufficient.
Here's all that digitrax has to say about it:
http://www.digitrax.com/tsd/KB326/dcs100-and-db150-power-supply/
They note that 12 V is the minimum voltage both AC and DC. I would read the voltage being supplied by your 4.2 amp supply while the DCS100 is powered on to be sure it falls slightly above the 12V minimum. I'm sure the current draw would be well below the 4.2 A.
Ed
A 5 amp command station and 4 or 5 boosters seems like overkill unless you will be running a LOT of trains. Perhaps you could save a considerable amount of money by using a DCS-100 and a PM-42.
In answer to your original question, I would use a power supply that exceeds the 5 amps the DCS-100 is designed for. Using one that maxes out at 4.2 amps can result in voltage drops if the load gets near the limit of the DCS.
Dave
Lackawanna Route of the Phoebe Snow
OnewolfI plan to use a DCS-100 as the DCC 'brain' for my layout and I will use 4-5 DB-150s as boosters.
The DB200 is only about $16 more than the DB150 and it gives you 8 amps vs 5. 3 or 4 DB200's will cost less and provide higher capacity than 4 or 5 DB150's.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
Modeling BNSF and Milwaukee Road in SW Wisconsin
Couple of points people seem to have missed.
First, check out Onewolf's posts in the Layout section to see just how big a layout he's building - operating alone it wouldn;t need that much power but get a bunch of people in there runnign trains and it will definitely exceed 5 or 10 amps. Plus sometimes it's not the amps you need, but the wire drop you need to avoid that dictates adding boosters. Even a hanger size layout where at most 2 trains are running doesn;t need more than 5 amps of power, however the length of wire runs would have trains going half speed due to the voltage drop - so you add additional boosters closer to the point of consumption even through you may not absolutely need 15-20 amps total power to run the layout. Boosters just happen to come in 5 amp increments. Overkill would be if they were all 10 amp boosters. There are the Tam Valley ones at 3 amps each. Using 8 amp DB200's is also overkill for the same reason - not to mention 5 amp power supplies are effectively a dime a dozen, whereas an 8 amp power supply is not a common item and costs a lot more, so the 'savings' aren't nearly as great as the price difference would suggest. 5 amp is common because they are laptop power supplies - that's what the new Digitrax 5 amp power supply is, as well as the small brick types included with other brands now.
Second, the DCS100 won't need full amps - he is not connecting any track to its output. This is a common best practice with club layouts as well, with no track connections to the main command station, it is isolated from dirty electrical signals on the rails which are often the cause of erratic operation - remember, it is a small computer and stray voltage spikes can scramble the brains. We run out modular layout that way, the DCS100 command station only has Loconet connections to the DB150's that actually supply track power. The NTrak guys do the same thing.
All that said - 12V DC is too low. The first thing inside the box is a full wave rectfifier so the DCS (and DB) can run on AC or DC input. With an AC input, the loss in the diodes is more than made up for by the filtering capacitor which gets you peak voltage - 12V AC, minus 1.4 volts from 2 diode drops (depending on where in the waveform you are, any 2 diodes of the bridge will be conducting) is 10.6 volts - RMS. Feed that through a filter and you get sq root of 2 x that - almost 15V filtered DC. But feed in 12V DC, and you get 10.4V DC out, because of the diode drops. The 4.2 amp rating is plenty if no load is placed on the track outputs. It's probably easiest to just get another of the same supplies you plan to use for the DB150's, even if you don't need the current capcity - they are probably cheaper than some special power supply plus that way you have a spare. Our DCS100 on the club layout uses the exact same power supply as all the DB150s, even though it too has nothing connected to the rail outputs. In fact, speaking of spares, if you need 5 of them, I'd buy 6 so you DO have a spare on the shelf. We once had to run one section of the layout with a 12V AC supply instead of the 15VAC ones because there was no spare handy, so trains slowed down a bit on one section of the layout. Now we keep a spare of each in the equipment box (the 12VAC ones are used to power lights and stuff).
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Just to make sure everyone understands the question, I'm not going to use the DCS-100 as a track power booster. It will be used purely for DCC command/control across LOCONET. There will be nothing connected to the DCC track leads.
Does it really need 13-15-17 volts if it's not acting as a track power booster?
The reason I have four DB-150 track power boosters (+1 for turnout power/control bus) is related to layout geography and the 30 ft limitation for 12GA DCC track bus wires.
I just noticed Randy's reply. :)
Randy, thanks for providing the background information on why I'm configuring the DCC boosters the way I am. I sometimes forget not everyone is 'up to speed' on the layout engineering project I'm knee deep in. :)
And big thanks for providing exactly the information I need regarding a power supply for the DCS-100.
I have a Digitrax PS 2012 that I will use to provide power for the DCS-100 and two DB-150s in my 'central' command/control location (one DB-150 is track booster #1 which drives a PSX-4 and the other DB-150 will drive the turnout power/control bus (which should not have the bus length limitation of the track power busses)). I have three DCC Specialties Magna Force MF615 (15v 5a) power supplies I plan to use for the 'remote' DB-150s.
Thanks for all the quick replies!
Just make sure you get an extra splitter cable with the 5 amp fuses - I think the PS2012 only comes with one. The PS2012 is only capable of 20 amps at the 12V setting, it's less when you turn it up to where you need it, but this is fine since you are only putting 2 real loads on it, the DCS100 with no track connections should draw well under 1 amp.
As to the question - yes, it does need the voltage - it just doens't need the amperage if it isn't supplying track power. The circuit needs the proper voltage to function, but won't draw much current if the track connections go unused. Even if you do connect a piece of track to the program track outputs to use it for programming - current draw will be minimal.
OnewolfJust to make sure everyone understands the question, I'm not going to use the DCS-100 as a track power booster.
What did I miss???
Again, Digitrax says 12 V. minimum. (link provided above) So try it with the power supply you have and if it does not do the job get one with a slightly higher output.
Regards, Ed