lionelsoni wrote:Bruce, you need only look at the almost total lack of anything resembling scenery on my layout to realize that everyone here has something he doesn't understand or do well. The strength of the forum is that we can help each other out with what we do understand, so that everyone comes out better off.
Bob has helped me a lot [and I know a lot about basic wiring]. Sometimes I have to say, "Bob splain it to me in English." Then he knows I have to have it broken down to learner's level.
God bless TCA 05-58541 Benefactor Member of the NRA, Member of the American Legion, Retired Boss Hog of Roseyville , KC&D Qualified
Neil B. wrote:Bob and Dennis,What word would you like to see used for the wire going to the outside rail?"Common" to some of our readers can suggest the wire is being shared, which in some wiring diagrams is true, but in others is not. "Ground" to toy train hobbyists gets confused with the ground on extension cords or "earth ground" for metal bridges, etc., on a TMCC layout. "Return" suggests, again to typical hobbyists, that AC is a one-way street.Seriously, I'm open to suggestions!Thanks,Neil Besougloffeditor
I think we're making mountains out of molehills here. The terms "common" and "ground" have been used for years by toy train electricians and as long as everyone understands its application to toy trains, then I don't see what the problem is. A socket for example is a female part to both pipe fitters and bone doctors. To a doctor a socket is the female part where bones connect. To a pipe fitter it is part of a pipe fitting where a pipe is inserted and welded. Who is in error here?....nobody really. It's the same jargon used by different trades to mean different things.
There are actually three standard symbols for ground-common type things: The "common" symbol is an open triangle whose only significance is that it is connected to all other like symbols. There is an option to put a distinguishing character inside it if more than one common is needed. The "chassis" symbol is a horizontal line with several short diagonal lines dangling from it and represents a connection to the box that the equipment is in. The "ground" symbol is several horizontal lines that would fit into a triangle and means an actual connection to the earth or, the one exception, the frame of a vehicle.
There is, to be sure, a lot of loose usage that confuses all three of these concepts with each other. This does not mean that the distinctions among them are unimportant or useless. A schematic diagram that misuses them may be understood if the reader correctly guesses what actual connections are meant. I feel that it is better to use the standard symbols and terminology than to rely on the inferences of the reader.
But none of this addresses the use of the word "neutral" in the magazine, which is to my mind a more serious offence, on the order of calling any electrical problem a "short". It oversimplifies a useful concept, the neutral, to the point that we lose the name for it in order to provide another synonym for the already conflated terms "common" and "ground", in the same way that we lose the ability to clearly distinguish a short circuit from other faults when that term means "any failure" to the reader.
May I add the observation that since the discussion of ground, common, neutral, etc. is entirely about what these words mean, it is of course about semantics. This does not however mean that it is not worthy of discussion.
I think you're agreeing with me, Dale, that tripling the capacitor's voltage rating is a waste. In this case, space seems to be at a premium, which is why I would recommended keeping the voltage rating as low as the supply will allow. Taking Rampolla at his word, the track voltage is about 12 volts RMS, or perhaps 13 to allow for rectifier voltage drops. My suggestion of a 25-volt rating would allow about 19 volts RMS on the track, which I suppose might produce a pretty good velocity. Thirty-five would indeed be bullet-proof.
Bob Nelson
lionelsoni wrote: My suggestion of a 25-volt rating would allow about 19 volts RMS on the track, which I suppose might produce a pretty good velocity. Thirty-five would indeed be bullet-proof.
My suggestion of a 25-volt rating would allow about 19 volts RMS on the track, which I suppose might produce a pretty good velocity. Thirty-five would indeed be bullet-proof.
Except it isn't. Joe and I have corresponded a lot over the past couple of years, and he actually shared this circuit with me long before this article was published in CTT. In one of his initial designs, he used a 35v cap, and he found it was getting too hot. When he stepped up to 50v, the cap stayed cool.
I'll say it again. Joe actually tried this circuit with a 35v cap and he didn't like the results.
Space indeed is limited in this application, but excess heat is also a concern, and heat in tight quarters is an even bigger concern.
Dale Hz stated that using a too-large capacitor isn't a problem. This weekend, after I saw this thread, I asked an old friend of mine who is also an EE if there would be anything wrong with using one that large. He said no.
Having read a story of a trolley bursting into flames in the very pages of this magazine within the past year or so, I'll gladly cast my vote with Joe Rampolla on over-engineering the solution, rather than going with the minimum that gets you by. I'd rather spend a few extra dollars up front to have something that runs cooler and lasts longer.
My 8th grade science text book had a picture of a train layout with a single break in the rails of an oval, and the caption that the train wouldn't run because the circuit wasn't complete. My 9th grade text book had a simmilar picture. Both years, there was also a test question regarding this. I was given the benefit of the doubt in 8th grade(since the teacher knew me well enough to know what I was talking about). In 9th grade, I missed the question despite the fact that I even set up a point-to-point track on one of the lab benches to prove my point.
The presumption was always that there had to be a complete oval for the train to run, which of course we all know is not the case.
Please note that I did not say that there is anything wrong from an electrical point of view in using an overrated capacitor, only that it was a waste of space.
A 35-volt capacitor should be good for 35 volts. This is the peak voltage when the RMS voltage is 25 volts, as much as a type-Z transformer puts out. I can think of some possible explanations for why one would get hot:
It wasn't really a 35-volt capacitor. It could have been defective from the start; or it could have been old. An electrolytic capacitor with time loses its ability to withstand voltage if it is not used at that voltage for a few years. (They can be "re-formed" and put back into shape.)
The peak voltage was higher than 35 volts. A phase-control transformer (like the CW80) can put out a high peak voltage even when set for a modest RMS voltage. However, 35 volts peak is more even than the CW80 puts out.
Whether one of these is the explanation, I don't know. But the practice of using an aluminum electrolytic at or near its rated working voltage is well established and is not considered at all risky. An analogy with mechanical engineering: If a bolt fails, you might triple its diameter to get a margin of safety; but tripling its length won't accomplish anything.
It occurs to me to add that all of my locomotives are converted to DC, with rectifiers and filter capacitors. Because of space limitations, many of these are rated as low as 16 volts (I have a boxful, salvaged from old equipment at a former job), with the expectation that I would replace them until I got ones that I could form to work at the somewhat higher actual voltage. So far, they don't overheat and none have failed.
Hello Bob:
Why do you use DC?
Regards,
John O
FJ and G wrote:Interesting. I wouldn't have known otherwise. Perhaps they could post this in their errata or erotica column.
Erotica?????
WoW!!!!! I have to start paying more attention to CTT!!!
underworld
jefelectric wrote: Now if you could come up with a wireless battery charger, that would be a great system!
Now if you could come up with a wireless battery charger, that would be a great system!
I think Tesla invented one of those...seriously!!!
John, I use DC on the locomotives because I have a homemade way to run two trains on the same track. I have synchronous rectifiers built into my Z transformers so that one knob controls the positive half-cycles and another knob the negative ones. According to whether the locomotive is rectifying the positive or negative peaks, it responds to only one control.
The locomotive rectifiers are actually modified bridge rectifiers, with a couple of switches to allow me to select the polarity to be rectified, or to shut it off entirely, or to use the full wave, which is handy for running on others' layouts.
I can also assign a steam locomotive's motor to one control and its air whistle to the other, allowing me to play with the whistle sound instead of just turning it on and off.
Impressive!
Are the rectifiers in the loco chassis, or the tender? If I understand correctly, the Z has four outputs, correct? How do you connect more than one output to the same track? Can the engines go backwards?
Having asked those questions, Am I to understand that you can have two trains on the same track, using one of the Z knobs to control one train (say, set to the positive AC cycle) and another knob to control the other train (set to the negative AC cycle)? Could you build in the same type of rectifying controls into a KW?
This is pretty cool.
The rectifier is in the locomotive.
I use three of the Z controls, one through the positive synchronous rectifier, one through the negative synchronous rectifier, and one straight--no rectifier--all three connected together. I have to observe the rule that the unrectified control always be off when either or both of the others is in use. (I have an idea how to make this automatic but I haven't bothered to do it yet.) I use the fourth control for turnouts and accessories.
Each of 5 blocks has a center-off SPDT switch to select the triple-control output from one of the two Z transformers.
The locomotives retain their e-units, which work in the usual way, but off the DC that the locomotive's rectifier has selected, not directly from the track. This requires that the e-unit frame (and the headlight socket) be insulated from the locomotive frame, which is a bit of a nuisance to do with older locomotives.
You've got the idea right: One knob controls one train, another knob the other train.
Yes, you could build it into just about any conventional transformer. Each synchronous rectifier is just a silicon-controlled rectifier with a one-transistor driver that turns it on when its transformer roller has the desired polarity of voltage. So there are two, one of each flavor, in each transformer case. This kind of active rectifier is necessary, as opposed to a simple passive diode, to keep the two outputs from driving each other through the diodes when the voltages are set to different values.
I would not deny the authors credit for what is correct and useful in their work. And I am sure they put praiseworthy effort into writing the articles. But I don't think that puts them above criticism. Kalmbach, and the authors presumably, profited when I bought the magazine; and I think that gives me the right to point out what I see as errors, particularly when I think that doing so may help someone, with these or other projects.
And, although you may disagree and of course are entitled to, I do still regard them as errors, just as I stated in the first post. So I think I will leave the subject line as it is.
I appreciate Bob's comments and critique. This is a true story...... In Jr. High I took a couple of courses in DC Theory, and was doing OK. Then assisted my Dad on some AC wiring at the house, since he was an old farm boy, and his training consisted of practical experience. Things were done his way. Nevertheless, I did have great admiration for him and his wisdom, and took what he said as gospel. Didn't take anythme at all, and I was totally confused. Black wasn't negative anymore, it was "ground", "hot" was white, and red wasn't used. OK. So there are different rules and customs for AC and DC.
Then start talking to some train guys.. and they run on AC using red and black wires. OK, then the assumption Black is Neutral, which Is Common, which Is Ground, and can be Chassis Ground. Then when working with AC typically White is hot, or incorrectly assumed as positive, then Red is OK, or even White, but not on trains, cause that may sometimes be ground. No wonder their is confusion.
Now try to go sort it out when your 17 or 18 today, and all the tech classes have been eliminated due to budget cuts, and more important classes like Home Economics, and being a Teacher Aide. So unless those that don't have the opportunity for formal education where do they get to learn correctly? Or, should all convention be thrown out, and then things have to be Untaught, or a very limited understanding? Or reamin PC.
Don
I was reading that at one time, I think it was in the 1920s and 30s, many houses were powered by DC so Lionel had to made a reducer to reduce voltage to useable levels. Bob has one (shown here). I believe he told me that if you hook it up wrong (the plug prongs are identical so it can go in both ways), it will shock the heck out of you and fry anything that touches the rails.
Your thread Bob and obviously your call. Just a suggestion related to the subject matter of the last 1-1/2 pages of the thread.
Based on your comment, presumably if CTT were losing money you would not feel you had the right to ctiticize their work.
lionelsoni wrote: I think that gives me the right to point out what I see as errors, particularly when I think that doing so may help someone, with these or other projects.And, although you may disagree and of course are entitled to, I do still regard them as errors, just as I stated in the first post. So I think I will leave the subject line as it is.
I think that gives me the right to point out what I see as errors, particularly when I think that doing so may help someone, with these or other projects.
And I hope you got your money's worth, because Neil Besougloff and Joe Rampolla sure didn't.
There's a perception that authors are rich. I guess people look at the cost of books and magazines and assume authors get half or a third, or some significant amount. Not true.
It's been a while since I've looked at the rates CTT pays, but if it's like most magazines of its size and circulation, Joe Rampolla's article probably put around $300 in his pocket. That's before expenses and before taxes. Since it's self-employed income, the government will take about a third of it.
Rich authors are rich because they sell millions of books. What they make on a per-book basis is very little. It might pay for lunch--off a value menu. Those are the sweetheart deals. The royalty on a "Dummies" book is closer to 25 cents per book.
I don't know exactly what a magazine editor makes, but considering the grief a magazine editor has to take--grief from irate readers, irate advertisers, irate would-be authors, irate authors--some days it's not nearly enough.
If you're tired of seeing the same thing over and over in magazines, this is a big part of the reason why. How many hours would it take you to write a 4-page article? Someone who does it every week can probably do it in about a day. It'll take a lot longer for someone who does it less often. And that's not even counting the time spent on the phone or e-mail convincing an editor that the article is a good idea, taking the pictures, gathering it all up to send in, proofreading the edited version, and the other administrative work. That's another couple of days' work.
It doesn't take very many people wanting to get their $5 worth of criticism in for an author to decide it isn't worth it anymore. So you tend to see the same set of authors who found a "safe" specialty that keeps most critics silent.
You're right, you have the freedom to say whatever you want about the magazine, even if you didn't pay for it. That's granted by the Constitution. But how many would-be authors are afraid of a thread like this popping up with their name in it someday?
I've published a number of articles and a book myself, almost all computer-related. It's really nice seeing your name in print in a magazine, and having a book on your shelf with your name on it. I can only think of a couple of times that I got a really harsh letter from a reader, but one of those made me do the math, and I figured out that I was making less per hour writing than I would make moonlighting at the local burger joint.
And guess what? I haven't published all that much since. Like Zeuxis said, criticism is easier than craftsmanship.
I agree that some off-topic stuff got in there, but I think not more than we're used to. That wouldn't lead me to withdraw my characterization of the items as errors, however.
I would say that paying six bucks or so for the magazine is a sufficient justification for criticism, but not a necessary one.
As a relative newbie to the hobby, I have learned a great deal in the past year from magazines like CTT, OGR and from their associated forums. I have, on a number of occassions, become confused by conflicting uses of terminology. To that end, I echo Don's comments above that having a consistent, correct vernacular, is preferred. This enables me (and I presume others) to gain a better understanding of the topics that are discussed, thereby becoming more proficient at this hobby.
Bob Keller
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