4、doflow-voltagedistributionandautomationcontrol.Soconsistency of performance oftheACcontactorhasgreateconomicsignificance.Butfurtherdevelopmenthassofarbeenconstrainedbyitselectricallifewhichbelowthemechanicallife’slevel.Thedirecteffectonelectricallifeiselectricarcthathasproducedinswitc