... at factory or jobsite.-Test CT/PT excitation curve and 10% Error curve by 0.5 Hz low frequency method;-Test ... CT parameters automatically: ²Knee point voltage/current, 10% (5%) error curve , ²ALF (accuracy limiting factor), FS (instrument security factor), ²Vb ... s parameters: knee point voltage / current, 10% (5%) error curve, the accuracy limit factor, instrument security factor, second time constant ...