Okay, third time posting (but this time, hopefully on the right forum):
We have a pre-war Lionel O gauge set that has been passed down. The engine was cleaned and refurbished professionally. We would like to use it this Christmas but do not know how to wire the transformer.
The transformer is a "Multi Control TrainMaster" 110 Watt Type RW, 155V 60Cycle AC only. It has a lever contol for the volts, a black whistle button and red direction button.
The back of the transformer has 5 posts. The top row is A,U, and B, the second row is C and D.
How to I attach this to the clips on the rail (3 rail system)?
U to the center rail. A, B, or C to the outside rails. Using A will give you 9-19 volts, B 6-16 volts, C 0-10 volts. If you have a lockon (the thing that clips to the track), terminal 1 is the center rail, 2 is the outside rails; but you can probably see that.
(I think you meant 115 volts, not 155.)
If all you intend to do is hook your Type RW up to the track to run one train and nothing else, it is pretty straightforward:
For 6 to 16 volts variable (the throttle) designate post U as "common" and connect it to an outside rail; connect post B to the center rail.
For 9 to 19 volts variable (the throttle) designate post U as "common" and connect it to an outside rail; connect A to the center rail.
I wouled start with the first option. Some pre-war locomotives required a higher voltage than more modern ones. If yours is one of them and you don't get enough power, try the second optionl
Check out http://pictures.olsenstoy.com/cd/transfmr/ps6.pdf for a useful discussion of Lionel transformers. See expecially the chart on p.6 at the top right for various options with the Type RW.
We disagree on which rail to connect the U terminal to. It actually doesn't matter if all you are doing is running a prewar train with no accessories.
If you were to connect up any accessories that have a return common with the track, U to the center rail is proper for this transformer. In this case, D is likely the terminal you would use to power the accessory. Lionel inexplicably made their single-control and multi-control transformers different in this respect.
As you say, either way will work in this straight-forward application. You are correct in that early on Lionel established a cockamamie hook-up "convention" that used different designations for "common" depending on whether a transformer was designed to have just one or two-or-more throttles. What they accomplished was a confusing (albeit versatile) wiring convention that has bewildered virtually everyone concerned, from the customers to their own employees, virtually until this day. I am speaking, of course, about the early "pre-revision" CW80's.
In view of this, I decided to cite the original Lionel materials from the era in question and rely on the horse's mouth, so to speak. Which end of the "Lionel horse" are you citing?
Before we confuse this member further, I think we can agree that U-B will provide the low range to the throttle; whereas U-A will provide the higher range. As you say, it really doesn't matter which goes to center rail and which goes to outside rail in this simple application. Agreed?
Thanks Bob. I woudn't have posted at all except for the fact that I was busy writing mine when yours popped up. I tried to emphasize simplicity and provide a reference, which I had to look up. (I can't get away with posting ex cathedra, as you can. ) Of course, "my" source supports your scheme at least equally to mine; and better if you add accessories.
What I failed to mention was that the opening paragraph of the source that I cited gives a better-than-nothing overview of the concept of "common ground" which I thought might be of general interest to the forum. Given the precise nature of the original question (at least as I read it) and the fact that its was the questioner's third try, I deliberately chose to eliminate all consideration of adding fixed-voltage accessories. In the end, your choice of options is more versatile.
One thing that neither of us pointed out was that the metal plate on top of the transformer likely shows all that really needs to be known -- if it's still legible -- right under the throttle pointer, showing the hook up posts for the two throttle ranges: AU high; BU low. It's amazing how many folks never see this; or, if they do, don't understand what it means. It is a feature common to many old Lionel transformers.
If I recall correctly, you employ an old Type Z (as opposed to ZW) transformer. One feature thereof is a max voltage output of 25 or so, which some pre-war trains might need. Or does the fact that most of the wall sockets now put out about 120 volts, as opposed to the 110 volts that were common in "the old days" mean that the "19" volts of the high range on the Type RW will actually measure in the low twenties, and be more than enough? (I'm not certain that was a sentence, but it was meant to be a question.)
Related questions are what do see as the normal house voltage at your wall sockets; and what is the max no-load voltage you can get out of your Type Z? Thanks in advance.
I actually use two Zs (and a T for the elevated track). I just took some measurements, with my best high-precision Radio Shack meter, and got: 125 volts on the power line, 115 out of my isolation transformer, and 25 maximum out of a Z.
The RW was specified for 115 volts; so I would expect only about a volt increase from running it at 120, 2 volts at 125.