KYORITSU 5406A - Page 15

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There is also another kind of RCD called "Type B", for which tripping is
ensured for residual sinusoidal alternating currents (like type AC) and
residual pulsating DC currents (like type A) and pure or nearly pure DC
current,whethersuddenlyappliedorslowlyrising.Itisalsoveryrarelyused
inpracticebecausetheseareonlyafewmodelsonthemarketandtheprice
atthemomentisveryhigh.
Tripping current I⊿ is the lowest residual current which can still cause
trippingoutRCD.
TheRCDtesterModel5406Astartstodrive test current from 20% of I⊿n
andthenincreasesituntilRCDtripsorupto110%ofI⊿n.
ThistestisnormallynamedAutoramptestanditcanbeusedtoconfirmthe
realsensibilityoftheRCD.
IfRCDtripsbeforethe50%ofitsI⊿n,therecouldbeacertainleakageor
faultcurrentthatisalreadyflowingtotheground,ortheRCDcouldbeoutof
characteristics.
In order to check the leakage or fault currents there are specific leakage
clampmetersasModel2432,Model2433,Model2413F.
TheRCDtesterModel5406AcantesttheTripouttimet⊿andtheTripping
currentI⊿.