In this case 60-Hz and 60A are useless information. 3rd harmonic phase currents are additive and are the highest in magnitude of the triplen harmonics (3rd, 6th, 9th). Each phase's harmonics contributes to the neutral current.
So here we have 3A of 3rd harmonic per phase so all we do is sum them up.
Third harmonic is a triplen harmonic. Odd harmonics add up in neutral. Harmonic currents are routed through neutral. In this case, harmonic curents in each phase route through neutral therfore current is additive in neutral.
3X 3 = 9amp
Does anyone know what happens in 3 phase three wire systems?
