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On the 1033 transformer, there is a "U" = common terminal (or what I always thought was common), and then A, B, and C "Hot" terminals. On the unit's face plate is:

A-U = 5-16 volts

B-U = 0-11 volts

Using the black lever, one can vary the voltage using the above combos.

However, what does the C-U deliver? I tried a test and it seems to deliver instantaneous power upon moving the lever.

To make this confusing, the instructions state that A-B = 5 volts; B-C = 11 volts; and A-C = 16 volts. Does that infer that C is a common, but than I would've gotten a short when I connected C-U?

What am I missing in understanding this?

Last edited by Paul Kallus
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On the smaller, single train transformers, you have the option to select different posts as the common.  In the chart below, each combination is provided.  However, it does not provide a voltage for U-C or C-U.  We might have to pull up the wiring schematic to see why... 

Typically, with the smaller single-train transformers, most would use the U as the variable voltage because you can also have fixed accessory voltage that maintains the same common ground post as the variable track power.  This would mean A or B would be most often used common ground post.

 

Transformer VoltagesHow to hook up transformers

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Last edited by JD2035RR
Paul Kallus posted:

What am I missing in understanding this?

"A" is the common on Lionel single throttle transformers, often using another post for an optional lower voltage range, with the 1033 it's B.

C-U will give you the same as B-U, only in reverse, and without overload protection. It will start at 11 volts and go down to 0 volts as you advance the throttle.

JD2035RR posted:

...In the chart below, each combination is provided.  However, it does not provide a voltage for U-C or C-U.  We might have to pull up the wiring schematic to see why...

 Backwards operation & no overload protection is a good bet.

Last edited by ADCX Rob
Steve24944 posted:

Never understood why...

The why, who knows, but the convention for postwar transformers(and continuing with the 4090 after 1969) is:

-single train transformers all have the throttle, direction, & whistle controls connected to the "U" binding posts for use on the lockon clip "1" or center rail
-multi-train transformers all have the throttle, direction, & whistle controls connected to other than "U" binding posts(A,B, D, e.g.), and "U" is for use on the lockon clip "2" or outside rails and is common in reference to the other posts on the transformer.

As far as I have experienced, the MW & RS-1 follow the 2 train convention if you consider the black clips on them as "U".

It would be interesting to hear or read about some of the design decisions of much Lionel’s postwar era. So many designs are ingenious, and really difficult to improve upon even 70 years later. 

It is my opinion that it was an intentional decision to allow different post to be common because it allows a wide variance of operating options. 

A youngster without much throttle control could keep the train on the rails if you opt for the low track voltage range of 0-11. Now the experienced young man could self-regulate and handle 5-16 volts. Even different locomotives require different voltages. Same goes for the fixed voltage options for switches and accessories. So it made all of the sense in the world to allow the transformer to accommodate all different uses.

The amazing thing is that they produced it with the end user in mind and not merely produce a starter transformer at the lowest cost possible. 

Last edited by JD2035RR

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