Q&A for MCL-400IR

Is Ior leakage current measurement applicable only for Single phase and Delta connection three phase transformer system?: It is correct.
Ior leakage current measurement is not applicable for Star connection, V connection, Double power, Combination type and Scott connected transformer system due to the program of internal software.

The measuring result for Ior leakage current differs in each measuring range.: Io leakage current is used as the reference value for the calculation of Ior leakage current measurement.
Use the same Io measuring range, the correct value will be displayed.

“-” polarity indication is displayed.: “-” polarity indication is displayed when the insulation of earthing phase is deteriorated.
Generally, “S” phase is earthing phase in Delta connection transformer system.
Although the leakage current is low in earthing phase due to no potential level, the insulation test during power interruption will show the insulation fault.