Most Helpful Member
hi V,It's an internesting Topic,
If you have a question ' Why it happens? ' ; then this would be the answer...
I think most of know how a transformer functions, the problem starts when you want to design a transformer.
Unless the transformer you need to design is unusual its a simple matter to buy a ready made transformer, its cheaper and quicker.
If you want to modify an existing transformer it can be difficult to precisely calculate its performance, as you dont know most of the transformers materials and characteristics.
If you are designing a specialised transformer for a particular function you would purchase the materials you required after looking thru the materials datasheets and applying the standard formula's.
When you have completed and tested the transformer, the chance of it functioning to 100% of the design criteria is doubtful.
I would tend to agree with Bychon's approach when answering the OP's question.