Parallel Operation of Transformers?

Question

How to connect in parallel the following transformers:
a) Dy1 & Dy11
b) Dd0 & Dd6

Answer 1

I don't recognize your transformer designations in a) and b). Perhaps they are industrial transformers that I am not familiar with. My background is electronics, not power distribution.

That being said, I'm not sure why you would want to connect transformers in parallel. Possibly to handle a load that exceeds the capacity of one transformer. If this is the reason, it would be better to split the load between two transformers if at all possible.

If it is a single load that can't be split, the turns ratios for the two transformers would have to be exactly the same. For that matter, the transformers should be exactly alike, to make sure that they carry the load equally. (A higher source impedance in one transformer would cause the other transformer to carry more than its share of current.)

Then it is very simple: connect like terminals together, taking special care to line up the phases.

If for some reason you are unable to identify the phase (commonly marked with a dot next to the winding on a schematic diagram), do the following:

1. Connect the primary windings together, wire 1 to wire 1, wire 2 to wire 2.

2. Connect one wire in the secondary of one transformer to a wire in the secondary of the other transformer.

3. Carefully apply power.

4. Measure the voltage between the two loose secondary wires. It should be zero. If not, change one of the wires in step 2 above.

Answer 2

does this make sense to any one?

delta /star 1 and delta start 11??

is thi 1 transformer with a turns ratio of 1:11??

question doesnt make sense?