YATQ (Yet Another Transformer Question)

I have a couple of these 14 pound transformers, so it's worth my time to figure
them out. Right now I have a question about the primary. It has two primaries:
one on pins 1 and 3, the other on pins 2 and 4. Usually with two primaries,
I've seen them hooked in parallel for 110VAC operation, and in series for 220VAC
operation. But this one has pins 2 and 3 jumpered, like they were in series,
and three wires went to the 'power in' connector: one to pin 1, one to pins
2 and 3, and one to pin 4. There is also a 110VAC fan accross pins 1 and 3.


Note: if the above is correct, it's an interesting way to use a 110VAC fan when
plugged into 220VAC.

Does it sound O.K. to put 110VAC across 1 and 3, or would there be any advantage
to using both windings in parallel (1 and 2 jumpered, 3 and 4 jumpered)?

I seem to remember there is a former transformer winder on this list, and I'd
appreciate some practical insite on how to use transformers.

Thanks for your time,

Steven Ciciora