DC to DCC Conversion

[rustyrails]

Jeff,
You keep that soapbox handy.  Since folks today never really interact with trains, they have no idea how to model railroads in a way that simulates the actions of a train.  I know that operation frequently gets bad-mouthed as too complicated, or some such, but the bottom line is that watching a train, I don't care how wonderful the models are, run in circles gets old awfully fast. 

My layout, when completed, is not going to be large--less than 50 sq.ft.--but it will use a card system to move cars on and off the layout and deliver freight, have a semi-working interchange, and have 30 inch radius curves to indulge my interest in passenger train ops.  I've "gamed" operating the layout and it's going to be a blast to run.  I expect to spend a couple of more years finishing the construction and scenery.  It's my last layout and I've no doubt it will keep my interest until I'm planted. 

Yet when I suggest to folks that model railroading is a lot more than figuring out how to run a UP Big Boy on 18 in rad curves, you'd think I was from Mars.  But, my experience is that once the last piece of fascia is nailed in place and the last feeder is soldered to the rail, there'd better be something more.  Back in the 50's, Peggy Lee sang a song called, "Is That All There Is?"  For those of us who answer "Yes," maybe RTR electric model airplanes will make us happy.  I doubt it.

Rusty

[jward]

rusty,
thanks for the post.
i am at the point now where i wish i had room for 30" curves. i don't, but that's not going to stop me. my gp40s will go around 18" curves that i am forced to use. my 6 axle power is in storage, awaiting that day when i can at least have 24" curves.

i agree about operation. my dad started a railroad back in 1978 based on operation, it is still in use in the basic configuration planned on paper, with minor changes in trackage to enhance operation. it was operated by card since day one, and still uses the same basic system. it has withstood the test of time well enough to be featured a couple on years ago in model railroad planning. if we'd have built a glorified circle layout, it would have been torn down a long time ago.

as with anything in life, you get out of this hobby what you put into it. don't be afraid to learn things, don't take the easy way out, and you will be rewarded. go into the hobby thinking you know what it's about , and don't put any effort into it, and you will quickly become bored with watching your trains run in circles....

operation complicated? yes, of course it is. i've worked for the real ones, they're complicated too, and sometimes have you scratching your head wondering what they are thinking. but when you put things in context they are also endlessly fascinating. model railroading is the same way. in what other hobby can you be exposed to carpentry, electronics, computer programming (dcc) geology, geography, historical research. metallurgy, and who knows how many other fields?

[WGL]

Tim, thanks again for the link to Litchfield Station.  I just ordered a Digitrax Zephyr from them, because they have the lowest price.

[klrwhizkid]

One thing that was missed in all the discussion was recommendation about the tools to do the job. The following link will get you to my suggestions about what to have to take on such projects: http://www.frisco.org/vb/showthread.php?t=2849 

I recognize that I am sending you off-site, but the frisco.org forum is free to all and I am the Electronics moderator there.  My suggestions come from nearly 40 years of electronics hobby.

[WGL]

 I received my Digitrax Zephyr Wednesday, two days from Arizona to Wisconsin!  It does run 4 sound locomotives (F7A-B included) on my 3 connected ovals.  However, they run slower than with EZ Command & its 5 amp booster.  The F7A-B passenger train reaches 80 with EZ Command + booster but only 50 with Zephyr.  I haven't found information about the length of layout as a factor in consumption of power, but I have about 117'.

  I succeeded in programming acceleration & deceleration momentum into my BlueLine Heavy Mikado & BlueLine SD40-2, both with Digitrax DN123 decoders.  I used a programming track so that I could read the existing values, all of which were 0.  I set the Mikado's momentum to 3 & 3; I set the SD-40-2 to 5 & 5.

  My BLI manual recommended programming the sound in operations mode.  I succeeded in reducing the master volume from maximum 15 to 10.

If I could be sure that it won't cause damage, I would try connecting the Bachmann booster to the Zephyr.  I will ask Digitrax, but I'm sure they want people to buy their boosters.  I posted the question on Yahoo\Groups\Digitrax & recived the following reply:

"Try the following at your own risk as it's only speculation based on the info
that Bachmann provides on their web site.

It should work. From the little info available on Bachmann's web site, their 5
amp booster is optoisolated same as the Lenz boosters. You would need to connect the track A and Track B terminals of the Zephyr to the inputs of the Bachmann booster. No ground (common) needed with optoisolation. Not sure if doing so would affect the use of the Zephyr's 2.5 amp track power to an independent power district. You may wind up with just the one 5 amp district available.
http://www.bachmanntrains.com/home-usa/ez_content/Images/booster.jpg

You could also try making up a special loconet cable with a standard 6 pin jack on one end to plug into one of the Zephyr's loconet ports. Strip the other end and connect only the outside (1 and 6) wires to the Bachmann booster input. Make sure you completely insulate the 4 middle wires. Not sure if Railsync will haveenough power to drive the Bachmann booster but it may just work.

With either method, you would still need to observe proper rail phase. Simply swapping the input wires at the Bachmann booster should take care of that.

Personally, I would try the Railsync method if I had a Bachmann booster around. Of course I've been known to blow up perfectly good equipment trying off the wall stuff."

[rustyrails]

How many feeders do you have to the track?
Rusty

I 

[Tim]

WGL

Your Zephyr is working properly.

The EZ command system applies a higher than standard voltage
to the track, thus the higher speeds.

The accepted standard DCC track voltage for H0 is 13 - 14v, the EZ command
is closer to 17v.

The Zephyr is designed to work with 15v max AC input, the track voltage will be ~13.8v.

Tim Anders
Souderton, PA

[Axim1]

Check out your area for a club or clubs and go visit them. There help and knowledge is without a dought the most bang for the buck. Plus they might even let you operate a train or two.

[Jim Banner]

If, as stated above, the E-Z Command Booster has optically isolated inputs, then connecting it to the output of a Zephyr is no problem.  With optical isolation, the only current path for the Zephyr's output current is through the IR LEDs inside the opto-isolators.  The amount of current the opto-isolators require is small, so the track outputs of the Zephyr can easily power them.  It is also possible that the rail sync outputs of the Zephyr could provide enough current for them as well.  But keep in mind that throttles also draw their power from the rail sync.  Rail sync is the two outer lines of the LocoNet, as explained on page 48 of your Zephyr manual.  Connecting these to the DCC input of your E-Z Command booster should provide enough signal it you are not using any LocoNet throttles, but even if it does not, optical isolation will prevent damage to the Zephyr and to the booster.  At this point in time, I cannot confirm that the inputs of the E-Z Command Booster are optically isolated and would really like to hear from someone who can.

However, even if the E-Z Command booster has optically isolated inputs, I would be very hesitant to try to use the outputs of both the booster and the Zephyr on the same layout, even if you have it divided into two properly isolated power districts.  The reason is the way the output circuits of Digitrax Boosters work.  Each booster has a single power supply.  The positive and ground outputs are switched back and forth between the two rails to make the DCC signals.  This means neither rail is ever more than about 15 volts above ground voltage.  By connecting the grounds of all the boosters together, you can never have more than 15 volts across any gap.

Other boosters may or may not use this scheme.  The MRC Power Station 8, for example, does not.  It uses two power supplies, one producing a voltage more positive than ground, the other producing a voltage more negative than ground.  (This is often called a "split" power supply.)  With this type of booster, one rail is held at ground potential all the time while the other rail is switched between positive and negative.  Generally, only one of this type of booster can be used on a layout.  That is because of the possibility of one booster applying +15 volts on one side of a gap while the other applies -15 volts to the other side of the same gap, a total of 30 volts.  The matching gap in the other rail will also have 30 volts across it, but the polarity will be reversed.  We now have a situation where a bit of dirt on the wheels and or on the rails can result in all of that 30 volts being applied to the decoder.  Not every time the locomotive crosses the gap, but it only takes once, for a tiny fraction of a second, and the decoder is toast.  So, only one booster if it uses a split power supply.

Now here is the dilemma.  I do not know for a fact that the E-Z Command booster uses a split power supply.  But then again, I do not know for a fact that it does not.  Therefore I would not be willing to connect its output and the output of my Zephyr to the same layout at the same time.

Two separate layouts, yes.  No problem.  In fact I installed a Digitrax command station with an MRC Power Station 8 booster for a friend.  He powers his basement H0 layout with the Digitrax and his outdoor large scale with the Power Station 8.  The Digitrax supplies the DCC signals to both.  A single layout, no.  I use a Zephyr as the command station on my own outdoor large scale layout and boost its output with a Power Station 8.  But I do not dare to use both the booster's output and the command station's output on that layout, much as I would like to have the extra power.

So there you have it.  If you can confirm that the E-Z Command does indeed have optically isolated inputs, then go ahead and use it.  But don't connect its output and the Zephyr's output to the same layout, at least not at the same time.

Jim

[Yampa Bob]

According to specs provided to retailers, the booster does have opto-isolation interface @ 30 ma. WGL's manual or DVD should have the information. Or not... 

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJFZ3

[Yampa Bob]

Update:
I found the following discussion on another forum, someone allegedly used an EZ Command booster with a Zephyr.

http://cs.trains.com/trccs/forums/t/28444.aspx?PageIndex=2

I don't know if the Bachmann booster is "linear" or not. We use Linear Current Boosters for our solar water well pumps. With the boosters, we get 8 to 10 hours of pumping; without the boosters, only 4 or 5 hours when the sun more directly hits the panels.

Your 4 sound locos may require more current than estimated. If each draws, say .75 amp, then that would exceed the Zephyr's output.  Did you check the speed of only one sound loco on the track? Then with two, then three, etc?

[Jim Banner]

Thanks, Bob, for the Tower Hobbies link.

For the record, the E-Z Command booster is not linear.  It has a fixed output voltage that stays (relatively) constant in magnitude but reverses polarity.  This is normal for a DCC booster.

Jim

[Yampa Bob]

You're welcome Jim. 

[WGL]

 Thanks, Tim, Rusty, Bob, Jim & Axim1 for your help!  I am impressed by so much response.

  I was surprised that Digitrax does not provide wires to connect it to the tracks, as Bachmann & LifeLike do.  I can use the Bachmann wires.  What is worse is the absence of wires for a programming track.  Today, I went to Radio Shack & bought clips to which I can solder wires, so I can connect the bare ends to the Zephyr & clip the other ends to the rails.  For $155, they ought to include program track wires.  The decoder & loconet cable tester they do include is something I may never use.

Rusty, I have one set of feeders to each of my 3 ovals.

Tim, I thought that an F7A-B passenger train would go faster than 50.

Thanks for the links, Bob.  I will test the speed of each locomotive alone on the layout & compare it with top speed under Bachmann.

Oh, I suppose my digital multimeter does not do what a rampmeter does. 


Bill

[WGL]

 I tested the Digitrax Zephyr with each train alone on the layout.  The Intermountain F7A-B reached 54, compared with 50 when all 3 trains were on the tracks & running, compared with 80 with EZ Command + 5 amp booster.  The BlueLine Heavy Mikado reached 79, compared to 118 with EZ Command + 5 amp booster.  The BlueLine SD40-2 reached 55.

  Strangely, the SD40-2 pulled its 14 cars at 100 with EZ Command, before I programmed its CV3 & CV4 from 0 to 5; then its top speed dropped to 67 (70 with no other locos on the layout)!  I reduced CVs 3 & 4 to 3, but the SD40-2's top speed remained the same.  In contrast, the Mikado runs just as fast with its CVs 3 & 4 increased from 0 to 3 as it did when they were 0!

Let me confirm, Jim:  If the Bachmann booster has optically isolated inputs, I can connect the Zephyr to the booster & the booster to the track, but connecting both the Zephyr & the booster to the track, even insulated districts, should not be done.  I wouldn't need 5 + 2.5 amps, anyway.  Now, I had to switch the Bachmann booster from 14 volts to 18 volts with EZ Command, because 14 volts yielded no more power than EZ Command alone.  Because the Zephyr has a lower voltage than EZ Command, should the booster be set back to 14 volts?  Would 18 damage the Zephyr?

I found that I didn't need to solder the wires to the alligator clips.  With the holes in their handles & their plastic sleeves, I just had to hook the wire through the hole & replace the sleeve.