There's a long history of 400hz power in computing that goes back to early supercomputers like the CDC 6600. https://en.wikipedia.org/wiki/CDC_6600?wprov=sfti1

There's a long history of 400hz power in computing that goes back to early supercomputers like the CDC 6600. https://en.wikipedia.org/wiki/CDC_6600?wprov=sfti1 https://en.wikipedia.org/wiki/CDC_6600?wprov=sfti1 CDC had a defense contract for early air data computers, used in the F-18. That business survives today as part of General Dynamics. https://gdmissionsystems.com/airborne-systems https://gdmissionsystems.com/airborne-systems