I have an RW and a ZW, and I know how to conect them together so that the locos run across the block from one transformer’s control to the other. Further, I want to create a constant low track voltage option, as proposed 50 years ago so that a train will slow down but not have the e unit cycle when you need it to yield to another train as in a crossing situation, I strongly want this to be powered out of the RW, not the inner rings of the ZW. Is this possible?
The back of the RW does indicate low fixed voltage terminal pairs, but they don’t involve the use of the U post which clearly is involved if I want to use my RW throttle during normal operation. If there is a way to do this, it must involve one or the other of the lower terminals on the RW. As a first, I tried to use my understaing of how the Lionel variable voltage transformers are designed with post fixed taps ,and the variable tap that is the “speed” throtle in an effort to see if I could figure what terminal would give me the appropriate connection, but I couldn’t get it.
I imagine, but could be wrong, that since the U is used with either of two terminals to get 2 different variable ranges, the slider must be connected to the U terminal. Other wise how could those 2 terminals be involved in fixed voltage production with other terminals, as the back indicates? So I am completely defeated. What am I missing, or is this an impossible task?
I do know I could hook an old fashioned resistor in so that when the main voltage was turned off with a relay or toggle switch the lower voltage colud still be delivered to keep the train energized. Lionel used to show this as a strategy in their old operation booklets.
Can be done. Insulated track sections and phased transformers. I know Bob Nelson does not like to hook transformers together. He has some technical reason. I emailed him earlier for his suggestions. He is an electrical engineer and knows his stuff [some I have a hard time understanding]. The way I see it you can run the trains on a scetion of track and then when entering the insulated section, run them on another transformer. Use on handle of the ZW to run on the main fast line and the other to vary the voltage for the insulated section. If that is not what you want, use the lower fixed voltages for the insulated section. Insulation is the center pin is removed and a fiber on installed. On more modern track [like Realtrax that I use], removed the connector, dremel a good gap between track sections center rail. Connect the insulated center rail to the other power source. The phased transformers common can be continous and connected to the whole track [“main fast line” and insulated]. Do you know how to phase? I think the RW uses the U terminal as variable and the others as common. There is a chart that shows this but I do not have it readily available. Maybe some one has the transformer chart. then you will know which is fixed and which is varible and which is common.
I am studying the reply, but not sure I understand it. Let me tell you what I want to achieve, perhaps more clearly than I did before. I have a turnout where two branches with two seperate speed controls controlling them. One is on the ZW D circuit, the other on the RW Variable circuit which has the higher voltage rqange, and I believe is the A terminal on the Back of the RW (if you look at that back of the RW, it is the top left terminal. Stated output of that combination on the RW cover is 19volts. I want to wire in a relay so that when the turnout is alligned for the train on the branch controlled by the RW to proceed “through” the branch of the turnout, and coming out the “single” end (am I being clear?), the train on the other branch controlled by the ZW D throttle yields, but does not go dead, which causes the e unit to cycle to neutral. I have a relay whcih is setup so that under normal operating conditiions, the relay is de-energized and the power from the ZW flows throught the contacts to the branch. When I want that branch to yield to the line controlled by the RW variable throttle, the power which reaches the ZW controlled branch would come from another fixed low voltage source so that an approaching train on that branch slows almost to stall, but the e unit stays engaged; thus when a normal condition returns on the turnout, this train will proceed on its previous original ZW supplied higher voltage.
I know how to install the relay to do the above, BUT if the U terminals of my ZW and RW are connected together as you would with phased transformers, what other terminal on the back of my RW can be used as the low voltage circuit to rout throught the now energized contacts of the relay to the branch. You must remember the U terminals are installed as “return”—what terminal on the back of the RW can function as a low voltage fixed hot leg?
First the transformer terminals: The common terminal of the ZW is U and should be connected to the outside rails, as you already know. The common terminal of the RW can be A, B, or C, depending on whether you want a maximum voltage of 18.8, 12.7, or 9.9 volts. The U terminal is the one that should be connected to the center rail. This was Lionel’s confusing way of wiring single-control transformers differently from multi-control transformers. Assuming that you want the full voltage variable up to 18.8 volts for your trains, you should consider the A terminal the common. In that case, you will have 2.8 volts (relative to the common) available at terminal B, 8.9 volts at terminal C, and 18.8 volts at terminal D.
You should be using 14 AWG or heavier wire for the ZW, since its circuit breaker trips at 15 amperes, and 18 AWG or heavier for the RW, since its circuit breaker trips at about 6 amperes.
As Frank hinted, I do advise you not to run between blocks powered by different transformer outputs, particularly different outputs from the same transformer (like the C and U terminals of the RW). This is electrically equivalent to a short circuit. Furthermore, when you do it with outputs from the same transformer, there is no circuit breaker protection. The heavy fault current that flows does not pass through the circuit breaker; and your train or layout wiring or your transformer will burn up while the breaker never trips.
Running between differently-powered blocks is all too common, unfortunately. You can get away with it if the two blocks are powered at exactly the same voltage, waveform, frequency, and phase, or if you run quickly across the gap, don’t stall, and don’t mind any fireworks that may occur. Running between two voltages set deliberately different for speed control and from the same transformer is always a bad thing. However, usin
Thanks for the answers–You guys certainly understand Lionel’s wiring; I will go try out what you say; I hope your suggestions will help me install the type of system that I want at this particular tunout on my layout.
And no comment about 1955 and the Brooklyn Dodgers. Amazing–simply amazing!
Ok–I’m back to report failure–I had previously had my ZW connected to the RW by running a wire between the U terminals. The U terminals were also connected to the outer rails of the layout and the D terminal of the ZW was connected to center rail of one loop, while the A terminal was connected to the centrail rail of the branch. Under that setup, locos ran across the junction between the two blocks of track. As I understood the advise of Bob and Rob, the plan to link the two power sources involved connecting the U of the ZW to the A of the RW, which would both be connected to the outer running rails, and the U of the RW would go to the central rail. This boiled down to my reversing the wires on the RW. I did that, and then ran a train from a block powered by the RW across the turnout into a block powered by the ZW and then through another turnout again into the branch controlled by the RW. At both gaps, the loco when bridging the two blocks created a short circuit. I never even got to test out the relay controlled low voltage circuit originating in the RW. Di I miss something?
You missed my comment that running across such gaps can work if the voltage, waveform, frequency, and phase are the same. You apparently got those close enough before by accident. But when you swapped the A and U connections on the RW, you shifted the phase by 180 degrees. If you want to continue down this road, unplug one of your transformers, rotate the plug by 180 degrees, and plug it in again.
Ok–I understand what you say about reversing one of the two plugs and I will try that this PM; It makes eminent sense to me, now that you suggest it; one never knows what the correct postion of plugs is until you make the coimmon to common terminal connection on the transformer, so it is logical that if I swapped the wires on the back of the RW, it would require a reversal of the plug of the RW at the oiutlet. Oh–I’m so excited–and I just can;'t hide it–I’m about to lose control and I think I like it!
Your work here seems to be done; Just came back from Lunch and had gone home to check out plug reversal to accompany my reversing wires on back of RW, and (not surprisinly) it works. Now I can use some fixed voltage terminal combinations off the back of the RW to supply a low voltage track power source for crawl but not stop voltage to preserv eunite function in turnout yield situation at my junction. Just Great–Thanks a lot!
I’m afraid I don’t share your enthusiasm. When you power the stop block from a fixed RW voltage low enough to stop the train and then run the train into that block with a variable RW voltage high enough to make it move, you are running across a gap between two center rails that you must have deliberately set to substantially different voltages. As the locomotive pickups, and any dual pickups on any lighted cars, cross the gap, they will create a short circuit, as I described above. It just won’t be as bad as the one you had yesterday, because the voltage difference is smaller.
I am going to re-read the two posts warning about going across the gap between 2 blocks at substantially different voltages, but It worked fine this evening; Train A stopped when the turnout was thrown in such a way as to energize the relay and create the circuit routing the lowere “crawl/stop” voltage to the rails, the e unit did not cycle, and the train resumed travel uninterruptedly after Train B had proceeded far enough for me to allign the turnout back to its usual position which de-energized the relay and re-established the original normal circuit.
You seem to be concerned about a condition I don’t understand or don’t appreciate; a further articulation of the concern would be of interest, but the results do seem to be sucessful, unless I am risking damaging the motors in a way you haven’t specified or I haven’t perceived.
Turn your variable RW voltage up and try connecting its U terminal to whichever other terminal you’re using for the stop-block voltage. Or set the stop block to the stop condition and connect the rails across the gap. The short-circuit that you create should trip the circuit breaker in a little while. (Don’t do this unless your layout is wired with no smaller than 18 AWG wire and are confident in the RW’s circuit breaker, which, fortunately in this particular case, is in the circuit.)
Ok, even last pm when I wrote my last post, I understood your point–You create a momentary short circuit based on the voltage difference, even though they connection is not “hot” to “ground” in a simple sense; it is still a direct connection between two poles at different potentials which creates the conditions of a short circuit, if only momentarily.
BUT–It is only momentary, and the trains do run, and it duplicates (I think) conditions recommended by LIONEL when they used to show use of a resistor across the gap made buy a fibre pin to create a stop/crawl block in which the E unit didn’t cycle. This was printed in a factory operation manual which I have from mid 1950’s; they recommend a 10 ohm 10 watt adjustable resistor on page 31. They make no comments about unfortunate effects.
The resistor method is fine, the “short” is really just a load on the resistor(or rheostat, if you want it adjustable). If you are using transformer windings for the difference, it is an actual short circuit from one point on the secondary winding to another, & no overload protection for the transformer. This could route the entire capacity of the transformer through the sliders/wipers and the winding taps.
Rob is right about “shorting” out a resistor. It’s a whole different thing from shorting out a transformer winding. As I said above, “However, using a suitably-rated resistor or other passive voltage-dropping element for speed control from a single transformer output is quite safe.”
I would like to qualify another statement that I made, “when you do it with outputs from the same transformer, there is no circuit breaker protection. The heavy fault current that flows does not pass through the circuit breaker.” This is usually true, but not in the case of the RW of a short between U and any of A, B, or C. The circuit breaker in that transformer is located between the fixed and variable sections of the secondary winding. The circuit breaker does not protect againse a short between U and D, however.
Although the circuit breaker is involved in what you’re doing and presumably your 18 AWG or heavier layout wiring can handle the overload if a train stops over the gap, there are other reasons not to. Many locomotives and lighted cars have two separate pickups wired together inside the unit with not-very-heavy wire that may not survive until your circuit breaker trips. Each pass over the gap also involves arcing, which you may find deteriorates your pickups and rails. It also creates inductive voltage spikes in the hundreds of volts which can damage modern locomotives’ electronics, if you have any.
By the way, as I think of what I have done, I am aware of seeing frequent references in old Lionel publications to using the fixed voltage terminals or inner ring throttles on a ZW to set higher voltages for up hill grades; Here also, would be a bridging of two different voltage circuits, in most cases on the same transformer. So Lionel must have been just as naive or unconcerned as I am.
You are correct, Lionel advocated this method at times. It kind of shows the rubustness of Lionel equipment that there were not more failures than have been discovered.
Bob Nelson has observed this type of failure in a Type Z transformer, I believe, and this would be the logical unit to find the most failures in if at all due to the high output they are capable of.
I’ve never had a failure with years of crossing blocks on all 4 of the ZW power districts on my current layout dating back to ~1971. It doen’t mean it won’t happen tomorrow, though.