DCC Booster

[Hunt]

Don,
I usually ignore spin and baiting but three things for others reading this thread.
  1.  As I have said before, I don’t speak for Bachmann or the Bach-man.
  2.  You should have already noticed the Bach-man rarely replies to a post with which he may disagree.
  3.  It is said, "A word to the wise is sufficient."
To that I will add… A word to the wise is sufficient but others are on their own. 

Bachmann’s recommendation I stated was already on their website about the use of a larger power supply with the E-Z Command Control Center unit when you first posted your experience using a more powerful power supply than provided by Bachmann.

Key caveat --- Others can expect the same results you have had using a more powerful power supply only if all the principal technical parameters are the same as you have or are compatible with the electronics of the E-Z Command Control Center unit.

One key technical parameter is known based on your representation. You have not yet exceeded the overload protection of the E-Z Command Control Center unit. Two key things that are not known are how robust is the unit’s overload protection and the maximum draw you are actually using.

[Jim Banner]

There has been and still is a great deal of misunderstanding about overloads in electronic gear.  Perhaps some explanation is in order.

Back in the old days when we controlled our trains with simple power packs, all the designer had to worry about was having a circuit breaker that would open before the transformer burned out.  As long as the current rating of the transformer was higher than the current rating of the circuit breaker everything was okay, right?  Well, not really.  If the transformer could heat up faster than the circuit breaker could trip, a sudden short circuit could destroy the transformer anyway.  Or if high ambient temperatures decreased the transformer's current rating more than it decreased the circuit breaker holding current, then again the transformer could burn out before the circuit breaker tripped.  The designer was faced with matching the circuit breaker with the transformer over a wide range of conditions, and still sometimes we managed to operate our power packs outside the safe area and our power packs still sometimes failed.

Introduce electronic components and there are a raft of new ways that things can fail.  They are mostly related to heat, but not always heat that you can feel.  Transistors, which we use to control the output currents of all command control boosters, fail if their internal temperatures exceed about 150 degrees Celsius.  But how their internal temperature relates to external conditions is what keeps electronic designers awake at nights.  There is the obvious heating from prolonged power dissipation by the transistors.  Just how much power the transistors can dissipate depends on their external temperature which in turn depends on the efficiency of heat removal and on ambient temperatures.  The designer usually limits this type of internal heating by monitoring the temperatures of the transistors using thermistors or other temperature sensing devices.  The closer the designer pushes the transistors to their limits, the smaller the transistors and heat sinks he can use and the cheaper (and more competitive) the final product becomes.  And, unfortunately, the greater the chance that exceeding the specifications of the device, even by a small amount, will lead to permanent failure.

Then there is the not so obvious internal heating of transistors that occurs when the maximum current rating is exceeded.  Exceed this maximum allowed current, even for a very brief time, and overheating occurs at microscopic levels inside the transistor.  If this happens enough times, the transistor fails and the device along with it.  External thermal monitoring will NOT control this type of internal overheating and failure.  So other schemes have to be used.  Excessive current can be controlled  by adding a bunch more electronic components.  However, the designer can minimize the number of extra components required and make the device more competitive by using an under sized power supply.  Then the internal impedance of the power supply helps prevent excessive current flow when a fault occurs.

When considering the device under discussion, namely E-Z Command, we see two things when we examine its wall wart power supply.  The most obvious thing we see is that the output is rated at 1000 milliamps (1 amp) which makes it somewhat under size compared to the 1.5 amp rated output of the command station.  Less obvious is that the wall wart contains what appears to be a temperature sensitive resistor (thermistor.)  I suspect this thermistor decreases the wall wart's output when it temperature rises from increased ambient temperature and/or from continued over load.  Ultimately, this thermistor should act as a fuse by burning out if the over load condition exists for too long, for example, if the overload protection circuitry in the device fails.

What this suggests is that the E-Z Command relies on the characteristics of the wall wart provided with it for continued safe, proper operation.  My personal recommendation is to NOT use any substitute, but if you insist, make sure the substitute has electronic current limiting to protect the E-Z Command or at least is fused at not more than 1.5 amps to protect the user when the E-Z Command current limiting circuitry fails.

And for the record, yes I am an electronics designer and have been designing power circuits, including model railroad control circuits, for more than forty years.  Not bragging, not complaining, just stating the facts. 

[Yampa Bob]

Hi Jim
Very well stated.  Some problems do arise when the manufacturer over simplifies their instructions for electronic equipment.  The manual for EZ Command is a masterpiece in clarity and brevity, a mere 8 pages. 

Perhaps the manual should include a few "should nots".  There are very few "NOTES", but there is one on  page 4 that is interesting.

"NOTE: THE 1 AMP TRANSFORMER SUPPLIED WILL RUN TWO LOCOMOTIVES AT ANY ONE TIME.  OPERATION OF MORE THAN TWO LOCOMOTIVES PER E-Z COMMAND CONTROLLER CAN AFFECT THEIR PERFORMANCE AND MAY REQUIRE ADDITIONAL POWER INPUT."

Now one could argue that they mean more power to the track, but we don't normally think of "track input", rather controller output.  Perhaps the note should say: ..... "MAY REQUIRE THE CONTROLLER OUTPUT TO BE BOOSTED BY AN OPTIONAL ACCESSORY".

The average consumer will replace a failed OEM walwart with a factory unit if available, or they may look for a similar unit at an electronics store. Unfortunately most of these do not have thermal protection. The uninformed consumer might even end up with a DC charger for batteries, so they might also warn that only one with AC output should be used.  The only hint is on page 2 where it says "16V AC IN".

Bob

[pdlethbridge]

I'll add this that if you add anything else to the system besides the 2 locos this will add to a burdened system. For instance, things that would tap off the 16 v AC such as lights for buildings and switch machines or more decoders that would control these items.
A good place to go would be Al gartner's site.
http://www.wiringfordcc.com/

[Hunt]

Hi Jim
Very well stated.  Some problems do arise when the manufacturer over simplifies their instructions for electronic equipment.  The manual for EZ Command is a masterpiece in clarity and brevity, a mere 8 pages. 

Perhaps the manual should include a few "should nots".  There are very few "NOTES", but there is one on  page 4 that is interesting.

"NOTE: THE 1 AMP TRANSFORMER SUPPLIED WILL RUN TWO LOCOMOTIVES AT ANY ONE TIME.  OPERATION OF MORE THAN TWO LOCOMOTIVES PER E-Z COMMAND CONTROLLER CAN AFFECT THEIR PERFORMANCE AND MAY REQUIRE ADDITIONAL POWER INPUT."

Now one could argue that they mean more power to the track, but we don't normally think of "track input", rather controller output.  Perhaps the note should say: ..... "MAY REQUIRE THE CONTROLLER OUTPUT TO BE BOOSTED BY AN OPTIONAL ACCESSORY".

The average consumer will replace a failed OEM walwart with a factory unit if available, or they may look for a similar unit at an electronics store. Unfortunately most of these do not have thermal protection. The uninformed consumer might even end up with a DC charger for batteries, so they might also warn that only one with AC output should be used.  The only hint is on page 2 where it says "16V AC IN".

Bob

Bob,
Some history, the use of the word input at the end of the note on page 4 you bring up in the E-Z Command Setup and Programming Instructions was raised shortly after the product’s first availability. I raised it in background not in the online forum.

Bachmann clarified for all the issue when it made available the online E-Z Command ® Digital Command Control FAQ --- Specifically http://www.bachmanntrains.com/home-usa/newez/index.php?ezpage=4#properpower

It would be preferable, to me, if they would also modify the note on page 4 in the online E-Z Command Setup and Programming Instructions PDF.

[gcodori]

How about you simply build your own booster and save some money (and arguements)...

the following boosters can be used on any brand system.

http://www.pdc.kth.se/~haba/slamra/dcc/booster/
includes thermal, signal and voltage protection

or

http://home.cogeco.ca/~rpaisley4/HBridge.html
minidcc booster - very simple - less than 10 parts to wire up.

[Jim Banner]

I looked at the mini boosters some time ago and felt that several of these, each powering its own power district, might be a better choice than one big booster and several circuit breakers.  And cheaper, to boot.  I see one seller on Ebay offering a pair of the LMD18200 ICs for $15 including delivery.

I have not tried this circuit out, but one conclusion I did come to was that you should use a separate power supply for each mini booster to limit the current in case of a shorted output.  Otherwise, you would be relying on the IC's 10 amp internal current limiting which is enough to weld wheels and melt turnouts.  This in turn would require connecting all the power supply negatives together to allow trains to cross the gaps between power districts.  There is also a small possibility that you would have to fit the inputs with optical isolators in order to parallel them.

If you insist on a single, large power supply, you could try using a LM338 based 3 amp current limiter in series with each booster's positive power input.  If this worked, and I suspect it would, the negative power inputs would automatically be tied together and optical isolators would definitely not be required.

[djp]

Hi Jim, CVPusa is selling a Booster3 for 50$ or something. Is it worthwile looking into it? I do not need anything more than 3A as i have a small layout and i don''t want to spend 150$ for the bigger boosters like Bachmann or MRC etc. Thanks.

[mattallen37]

Just build your own booster, it is pretty much just an H-bridge.

                                                       Matt

[Yampa Bob]

It doesn't hurt to have a little extra horsepower in case you expand.  The single booster sells for $79, but it requires the power supply at $55.  That's still reasonable. I would probably spend the extra $10 to get the single with reverse loop feature.

I ordered the power supply as I needed 24 volts to bench test solar pumps. Their peak draw is 4 amps so the pack is perfect.  The adjustable output is a nice feature.

Prices of boosters will drop as more are produced.  I remember my first calculator was $150, now you can buy a nice one for $5.

Bob

[grumpy]

Bob
Have you looked at the possibility of building a booster as per the posting of GCDORI. Is it a reasonable answer to the cost of purchased boosters.
Don

[Yampa Bob]

Frankly I haven't considered building one.  I spent all my life building things just to save money.  I intend pampering myself for the remainder of my life. 

You have to admit the Zonemaster is a very attractive unit for the money.  The thing that impresses me most is the label on the front  "Made in U.S.A.".

The brochure states the Zonemaster is compatible with almost all DCC systems.  A compatibility list is needed on the site.  There are several cautions listed, including compatibility to CVP3. 

The EZ Command normally connects to any walk around Companions with a data cable.  However the Zonemaster requires the data cable from the command station for input, and there is no restriction on the length of the cable.  With this arrangement, the term "booster" is perhaps a misnomer, as the track power output of the command station isn't connected to anything.   

This would also seem to preclude the use of a Companion. 

At the present time any booster, including the Zonemaster, is a low priority for me, so please address your comments to the general membership.  I'm just making observations.  Do your own research and draw your own conclusions, I've already had sufficient admonishment regarding boosters.

Thanks

Bob

[grumpy]

Bob
Thanks
Don

[Yampa Bob]

Don
You're welcome.
Bob

[Santa Fe buff]

Did you try e-bay?

http://search.ebay.com/E-Z-Command-Booster_W0QQcatrefZC6QQfnuZ0QQfposZ60914QQfpos1Z60914QQfpos2Z60914QQfsooZ2QQfsopZ32QQftrtZ1QQftrvZ1QQrprZ249QQsabfmtsZ1QQsacatZQ2d1QQsadisZ200QQsadis1Z100QQsadis2Z100QQsaobfmtsZinsifQQsargnZQ2d1QQsaslcZ2QQsatitleZEQ2dQ5AQ20CommandQ20BoosterQQsbrftogZ1QQsofocusZunknownQQxpufuZx

I think $100 is okay then.