1033 Lionel transformer

[Amtrak Steve]

I have a 1033 Lionel Transformer.  Which post is the "ground"?  There are four posts-U, A, B and C.  I understand that UA and UB are variable voltage.  Which do I use for the ground?  Also, can I use constant voltage to operate accessories while using the variable voltage settings?

One more thing.  If I purchase another 1033 transformer, what is the best way to put them in phase?

Confused.

[rtraincollector]

U

[TrainLarry]

The 'U' post is the common terminal. You can run trains and operate accessories at the same time, within the wattage limits of the transformer. To phase the 2 transformers, connect the common terminals (U) together, turn the variable voltage on both transformers up to the same point, and briefly touch a wire to both 'A' terminals. If you get a big spark, reverse the AC plug on one transformer and try again. You only need to phase transformers if you are running 2 trains on separate loops of track that are insulated from each other but are interconnected with switches. You do not need to phase transformers if one is used to operate accessories only.

Larry

[lionelsoni]

U is generally the common return for multi-train Lionel transformers, but not for those intended for a single train.  For these, like the 1033, use A or B for the common, depending on whether you want 5-16 volts (A) or 0-11 volts (B) and connect U to the center rail.  A-U is the only choice likely to give you enough voltage to run most trains.

Yes, you can use any pair among A, B, and C for a fixed voltage that suits your needs; but, for control-rail applications, the pair that you use must include the common that you have chosen to connect to your outside rails.  If you are running modern locomotives that make a distinction between positive and negative polarity for the whistle-bell control, you will find that connecting U to the center rail will result in the 1033's blowing the whistle (when you operate the whistle control).

By the way, the old Lionel schematic diagrams consistently show the rectifier in the whistle-control circuit connected backwards with respect to the usual modern convention.

[ADCX Rob]

A

is common on the 1033/1044/1032 type transformers.

[handyandy]

B-U is great for running old Marx tin trains. The older locos were designed for 12 volts maximum.

[lionelsoni]

Because the circuit breaker is between the B terminal and the 11-volt winding, it protects the transformer whether either the A or B terminal is used as a common.  The only consideration in choosing between A and B is the voltage range needed.  As the Lionel service manual says, "The two variable voltage ranges are:  Posts B-U, 0-11 volts; posts A-U, 5-16 volts."  As I suggested above, A is usually the better choice, by virtue of the greater voltage available, but it need not be if less voltage is needed.