Electrist
For figuring everything electrical nothing else even comes close. Try the free trial of Electrist and see why electronic engineers in some of the finest R&D laboratories in the world, industrial maintenance crews, power utilities, RF & audio engineers, circuit designers, telecom engineers, and... Size 3 phase panels & transformers with the built in load calculator. ... Enter any number & configuration of delta or wye/star and 3 phase, line-to-line, line-to-neutral, and/or centertap-to-neutral to instantly get both the phase and line loading in current, true power, and apparent power.
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