You can optimize the Farady transformer

In such a transformer, iron loss always happens at the same time as copper loss, and you can optimize the farady three phase pad mounted transformer to get the lowest total loss, regardless of how it distributes between the iron and the copper. Even more, you might intentionally place more loss into the core than the farady three winding transformer, based on the fact that the core is less prone to be damaged by heat, has more thermal mass, and that the short operation time won't allow the peak heat to distribute through the transformer! And then, such a transformer that operates only for short times can be designed to have a really huge loss, because it will have time to cool off between uses! These things are what makes microwave oven transformers that deliver 800 watts be as small as a 200 watt transformer intended for continuous service at low rate, and run at a flux density of 2 teslas or even more!