It's an easy oversightâ€¦ "E" in your formula is intended to be phase-to-phase balanced quantity.
Your voltage measurements were from connecting a meter phase-to-neutral... 120V.
The cure is repetition, repetition, repetition.
A sanity check may be looking at the stator leadsâ€”thinking, "Are these more like 70-amp leads, or are they closer to 200-amp leads?"
Working with transformers and capacitors use the same calculations, but take time and experience to make sense.
to memory, then beat into your head the cases where 3Ă¸ and square-root-of-3 apply.