In article ,
Robert Galloway wrote:
Maybe my imagination but motors running under load on a static converter
seem to vibrate. My imagination? Anybody else?

Reasonable enough -- as you really running it purely from single
phase after it spins up to speed. The available torque goes through
zero twice per cycle (that is, at 1/120 of a second intervals in the
USA).

Real three phase -- or synthesized three phase from either a
rotary converter or a VFD does not, as when the torque from one phase is
approaching zero, another phase is approaching peak, and a third is just
past peak.

People who replace a three phase motor on a surface grinder with
a single phase motor notice a difference (degradation) in the resulting
finish.

Enjoy,
DoN.

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