Yeah, I was wondering if I should go with a pair of transformers and if there is anything to worry about when doing so.
Hi
Quick and simple way to phase check the transformers:
1) Hook up the primary of each of the two transformers in parallel.
2) Hook up the secondary(s) in series.
3) Put a volt meter on the secondary series combo.
You will either get:
A) Secondary A + Secondary B on the multimeter
-or-
B) Secondary A - Secondary B on the meter
As long as you are careful staying away from the line voltage, there isn't much risk in doing this. Once you know the phase, a couple pieces of colored tape is about all you need to preserve that information.
The same process also works for "lining up" the phase on multiple secondary transformers.
One caution:
On multi primary transformers with unknown phase, start with only one primary connected. Be careful with the other primary since it will have line voltage on it. Generally the safest way to sort out unmarked primaries is to drive a secondary with (very) low voltage AC. You then sort them out just like the secondaries above.
Bob