35kv Class Three-Phase Copper-Wound on-Load Tap-Changing Power Main Transformer

For very small, low-power loads (e.g control circuits, lighting), this is acceptable. For anysignificant load (typically>5% of the panel's capacity), this will cause the dangerous loadiunbalanced discussed earlier. A dedicated transformer isthe only professional solution for high-power single-phase equipment.

They solve opposite problems. A 3-to-1-phase transformer takes three-phase power andcreates single-phase power. A phase converter (rotary or static) takes single-phase powerand generatest a third phase to run a three-phase motor. They are not interchangeable.

Modern dry-type transformers are highly efficient, typically in the range of 95% to 98.5% at full load. Efficiency dropsslightly at very light loads. The choice of copper vs. aluminum windings also impacts efficiency, with copper beingsuperior.