DC power supplies?

Probably because it was the cheapest option.

My assumption as a new owner of both a Lionel and an MTH RTR set, is ease of use.  With Lionel's DC power sources, there's only one thing to plug in, no wire harness to attach, less to worry about with young children, easy to transport, and etc.  Not to mention that you don't need the annoying line-of-sight DCS Remote Contoller box as with the MTC AC set. In computer lingo, the Lionel sets are true "plug and play" and they are really ready to run. Yet you can stick them on an AC track when/if you upgrade and they are just fine.

With the exception that one of my cars has reverse polarity wired lights, as some of you helped me uncover, I'm otherwise very happy with the DC power supply.

Tomlinson Run RR

Gunrunnerjohn has it right.  that's the all of it . . . 

And it is unlikely that DC would "blow" the boards on Legacy loco - it just would not work, maybe.  

Sadly, checking a DC circuit with your multimeter set to AC results in a voltage doubling. The result would be 36v DC being fed into the logic boards.

As far as cost goes, I've seen some pretty cheap 1-2amp AC bricks.

Say what?  I checked my bench DC supply set at 12V with three AC meters, two of them are true-RMS, one is a cheap Harbor Freight clamp-on.  I get zero volts on any of them on the AC ranges.  Connecting your meter to DC on the AC range or AC on the DC range won't damage anything.  The only risk is exceeding the maximum voltage for the meter, that's usually in the hundreds of volts.

I don't know what you're really trying to say here, but it certainly didn't come out right.

Sounds like these are the LC Sets, and they do come with 18VDC packs because the RC controller does the rest. Surely a cost savings method.  These engines also run on AC, so you can scrap the DC pack and use AC also.   G

Sorry for the confusion John.

Yes, I have several multimeters that do this. One is a Fluke with true rms. This is what I get with my cheap harbor freight one.

This could just simply be the arrangement of the diodes inside the meter. Regardless, I'm not going to put my legacy on a DC brick (as the book specifically says 'do not use DC').

Also I am aware of the LC's being able to run both DC or AC. I've cut the brick off and wired in a CW-80 for the kids.

Interesting, I have a FLuke true-RMS bench meter, it measures zero volts for DC on the AC scales.  All the meters I tried got zero volts except one really cheap thing that I was given with a collection of stuff, for 12 volts it did indeed get about double, 25 volts.

That is the oddest thing I've seen in a long time... I could see going the other way around being a problem, as say, an 18 volt ac from the transformer can make 25ish volts when converted to DC... but from dc to ac?  Can't think of a reason it would do that.  

The one cheap meter that does give the bogus indication works fine on AC or DC if you have the correct range selected.  Like I said, out of a total of five meters, it's the only one that indicates anything but zero when reading a DC input on the AC scale.

I still reference my trusty Forrest M. Mimms, III Electronics books. Depending on how the AC is converted to DC (Again arrangement of the diodes), this phenomenon is very much possible. Especially more so in a "common ground" environment.

This circuit is a prime example. The only difference between these two circuits is the "common" connection between the two capacitors (C1 and C2) and the AC side of the bridge. These capacitors would typically doing ripple rejection duty in normal circumstances (Removing remnants of the sine wave and making it as flat DC as possible).

Since Lionel isn't going to just cough up their schematics for their control boards, I am going to go with the "safe" assumption that putting my 400$ engine on a DC supply is an unwise idea (unless Lionel says otherwise).

I'll check this against some other meters I have. I grab the cheap ones as their either free from harbor freight or I'm constantly breaking the test leads (Usually the first reason!) and Fluke lead sets are a bit pricy to replace when they get snagged by some piece of machinery.

On another note, if this was a conventional pulmor, I wouldn't hesitate to run on a variable DC system.

Do what you think is best.  It's your loco so be careful with it.  

I've tested a few Legacy locos on 16 V DC just to see what would happen: they don't run, although some Lionel products (inspection vehicles, etc), do.  Instead they just quietly buzz.  Then back to AC and they run fine.  Seemed to be no damage and I really didn't think there would be.  But you never know . . . 

Better safe than sorry, yes?

You miss one important point Stone Rhino.

The question was why feeding DC to the meter on the AC ranges gets wild readings, your previous example was an AC to DC conversion.  It's quite common to use voltage multiplier circuits when converting AC to DC, no mystery how they work.

How about an example where a simple component placement makes the DC into double the AC?

Cost, which has been mentioned, is one.

I believe the other half of that, though, is simplicity and "foolproofing".  The DC power supplies can be plugged in - in any quantity - w/o regard to phasing on a connected loops layout, even if the wall supplies are plugged in to outlets with opposite orientations or on different legs of the 120/240 circuit.

Otherwise, we would be working on solving phasing issues with all of those recently expanded LionChief sets/outfits.

Never thought about the phasing Rob, but that's an excellent point, especially for the new novice!

As I said, "ease of use"! :-}

Who is worried about phasing a 2A PS on a Starter layout?  BUT, just swap polarity now instead of phasing.  Just takes a manufacturing error on the plug wiring to cause a real issue.

Face it, cost was the only issue.  Too easy to get a DC walwart made by any one, not many AC walwarts.  So DC was the cheaper choice despite bucking the AC tradition.  G

quote:

Say what?  I checked my bench DC supply set at 12V with three AC meters, two of them are true-RMS, one is a cheap Harbor Freight clamp-on.  I get zero volts on any of them on the AC ranges.  Connecting your meter to DC on the AC range or AC on the DC range won't damage anything.  The only risk is exceeding the maximum voltage for the meter, that's usually in the hundreds of volts.

At least some of the older analog meters that I own will show double the voltage if D.C. voltage is checked with the meter set to A.C. My Precision Apparatus 864 does. My Simpson 260 reads the same whether set to AC or DC.

The only place I've seen things like this done are UPS/Battery backup, and Inverters. Now, if you want a really, REALLY simple way to make AC from DC?

...Relay, Capacitor, Choke coil. Sure it will be incredibly noisy, but you'll get your AC from DC.

I have recently seen some individuals using some form of voltage multiplication in their cars for the purpose of running a custom amplifier, but its unclear to me why someone would want 92 volts DC from 12 for the purpose of amplification.

Anyhow, yes Phasing is a key issue. No doubt about that getting fouled out. I don't feel like watching a grown man break down in tears again.

This rhetorical question fortifies my opinion - nobody starting out should have to worry about it. The section in the starter set owners manuals about phasing has been deleted from the LionChief manuals.

Ok, but...you really think that was the driver?  How about more power under the curve of a DC signal?  Lionel has shifted to a DC board set with no common ground to chassis like the older boards and TMCC.   DC is an obvious choice because of cost, compatibility with new electronics and readily available parts suppliers.

You still have polarity issues so that is a trade off not to be underestimated, because of the more catastrophic damage if 2 fixed voltage supplies get connected out of polarity.  Especially if folks start trying to use larger not standard DC packs to power the growing layout.

Additionally, this DC power pack doesn't work with an expanding starter set layout. Operating tracks don't like it, and it shorts out the smaller pack.

So I think in the end it was cost pure and simple since much capability was lost when the shift was made.  Plus phasing for new products is pretty simple with polarized plugs now a days.  As long as Lionel sticks to the same internal wiring.   G

I think Lionel was doing everything it could to keep the LC and LC+ simple, idiot-proof, and bulletproof.  Using DC was one thing that helped.  

But DC was also the lowest-cost option.  Would they have picked DC for the "simple phasing" if it wasn't the lowest cost option?  Who knows.  But they didn't have to: it was.  In my experience a lot of times when "it just works out like that," it is actually because somebody was thinking well far ahead, arranging the big picture.  Here, I'll give Lionel credit for that.  I think they put a lot of thought and preparation into LC and LC+ before getting into the weeds with the details.

Lee,  I purchased the LC PE set for the Xmas tree.  Simple loop but I added an uncoupling section, into the oval.

Did not work with the DC pack.  Had to remove the track section, or go with an AC transformer with terminal track.

Does a starter set sold for a child with an add on remote control track work with the DC pack?  G

While picking up my carpet layouts for my cleaners today, I noticed that the DC Lionel RTR was lawyer-approved for 8 year-olds, while the AC MTH RTR was lawyer-approved for 14-year olds. Thus, AC requires an additional 6 years of maturity to "safety" connect two wires to a track.  So DC gets 'em hooked earlier on, and then they'll have nearly a decade more future years to spend on the more expensive/expansive power options.  Now that's strategy and forward thinking! :-).

Tomlinson Run RR

And you thought it was all hit or miss!   Those guys keep thinking over there at Lionel.

What seriously involved hobby, particularly any that involves technology at all, doesn't have similar, or worse, inconsistencies, "upgrade" paths, can't-do and must-do rules, and confusing nomenclature and this-will-work-but-that-won'ts to the novice.?  

Take shooting/hunting for example.  You buy a simple, light, easy to use and easy to care for 22 rim-fire rifle and a box of ammo for it: a starter set, but maybe not cheap (Henry commemorative railroad edition?).  You have fun with it. But soon you discover that there are many types of 22 bullets and yours can't fire some of the most appealing, etc. and they have serious advantages, and you need to upgrade.  Your discover there is a world of technical this and that and therefore, and whyfore that shapes what works and why.  You also learn the universal truth: the good stuff requires knowledge, skill, and money.  It's basically the same thing . . . 

Forgive me, but the Japanese have a word for Lawyers... "Shark"

Yes, bullet-proof wiring. Until you loose the power pack. That's how I get lots of fastrack for cheap. Thrift stores have the sets for next to nothing.

Larger layouts are going to need bigger packs. They sell up to a 72 watt DC pack that uses that same plug. Why not just direct tap an AC transformer? Hell I just found a 1500mA AC brick that looks just like Lionel's for 20$ (10$ if you're willing to risk eBay).

The ultimate resolution for me was to simply cut the DC brick off the wire, put a 12v transformer in a project box with a breaker. My total cost was 35$ and its child proof.

"But wait Joe, why 12 volts AC?"

Glad you asked!

As being part of Kids Run Trains; It became clear just how fast those Thomas sets really go. With LCCA's large radius turns of 72" and 86", the amount of speed these little engines can go is quite dangerous when not pulling a load. At 10 to 12v, these little bullets become a lot easier to tame.

Interesting, Stone Rhino.  I just got an MTH trolley that was set to "roadrunner speed", which was useless with both my Lionel and MTH RTR sets.  So I bought a used Marx 6-12 Volt transformer and it works just like your setup. I now have a well behaved trolley. 

You mentioned adding a breaker to your 12V transformer. Right now my Marx is plugged into a power strip with a trip fuse. But I have a feeling that's putting the protection at the wrong end.  Can you explain a bit more about what you did to add a breaker? Thanks (still a newbie but better than an 8 or 14-year old :-).

Tomlinson Run RR

When I set up remote Thomas and such for the grandkids I power it at 11 volts.  Plenty of power to run everything, but it keeps the maximum speeds down to something reasonable for five year olds.

How do you do that with the fixed 18VDC pack?  G

1 April Update: While reassembling my carpet layout, I noticed that my "new" 1960s Marx transformer claims to have a circuit breaker inside. I was looking for an external trip switch or fuse.  So, I guess I'm all set safety-wise, but I am still curious how one might add such a thing should I pick up any more old transformers to replace my current DC applications. Can't beat the $10 price.  TRRR

A 1950's PW transformer from MARX or Lionel is NOT sufficient protection.  It's pretty likely that circuit breaker no longer functions properly.

Gunrunnerjohn, I can attest to the fact that the breakers really didn't function well even in the 1950s.  My brother and I had a really exciting time one day running trains when I was about eight - the breaker didn't, and we had a small fire.  Nothing scary - we thought it was great, but my Mom, who was across the basement doing laundry at the time, freaked out. Fortunately, a bucket of water does nothing permanent to a Marx loco or layout: just let it dry out while you spend that hour in your room for causing so much trouble!

Yep, it's a rare PW transformer that has an effective breaker.  Yours is not the first story about a layout fire.

tomlinsonrunrr,

Here is a circuit breaker from forum sponsor Henning's which would be a big step in the right direction.

You can purchase reset-able breakers from any electronics distributor. They go in series with your load.

If I may point you at some

http://www.delcity.net/catalogdetails?item=70611

This is the one I used.

http://www.alliedelec.com/circ...avigation=4294852528

A nice list that would better match what you specifically need. Usually something like this, you want exactly the amps you're pushing.

Self-resetting are NOT a good choice.

Like I said, the fire was a lot of fun at age eight, but I see why my mother got concerned. When my Dad got home that evening he got all concerned about the black patch on the layout and installed a fuse holder in line with the feed to the track.  He and Mom thought that we didn't know where they kept the fuses, so we'd have to come ask each time we needed one, but we figured it out.  I think eventually he figured that we know, because his box of spare fuses lasted only about a month . . . 

Well, at least he know they were effective!