Does the BiTT transformer of Thane Heins have those limitations ???

[TinselKoala]

There is a difference between the "steady state" condition (tops and bottoms of pulses, or near the sine wave peaks) and what is happening at the edges, when the magnetic field caused by the moving charges is building and collapsing. The field building stores energy, the field collapsing returns this energy. When you open a switch in an inductive circuit, the field collapsing makes the current "want" to continue in the same direction across the switch, delaying the circuit's "turn off" time. This is the magnetic field's stored energy being returned to the circuit as the field collapses. We are all familiar with this. Less appreciated is the reverse process: when you close the switch in an inductive circuit, there is a delay in the current reaching its full value. This is because the magnetic field takes energy to set up. Speed the process up by sending a pulse train or an AC signal to the coil and you see a phase delay between applied voltage and current in the system.

[poynt99]

You apply current, you get the same current out which you can use, minus some losses. But you will also get the magnetic field. You did not apply any magnetic field in the wire, it comes as a side product of moving charge. If your current is DC you get electromagnet, if it is AC you can use it for power transfer via induction (fluctuating magnetic field). But you should know this so lets not distract this thread further.

The magnetic field is set up as a consequence of applying a current. The magnetic field most certainly did not come "free".