KYORITSU 5406A - Residual Current Device (RCD) Test; RCD Test

 11 
5. Residual Current Device (RCD) Test
5.1 RCD test
RCD is a switching device designed for breaking currents (opening the
contacts)whentheresidualcurrentattainsaspecificgivenvalue.Itworkson
basisofcurrentdifferencebetweenphasecurrentsflowingtodifferentloads
and returning current flowing through neutral conductor (for a single phase
installation).
IncasethecurrentdifferenceishigherthanRCDtrippingcurrent,thedevice
willtripdisconnectingthemainvoltage.
Fig.5
Basicallythere aretwo classificationsforRCD's :The firstone due tothe
shape of residual current waveform sensibility (Type AC and A) and the
secondduetothetrippingtime(TypeGandS).
● RCD typeAC, RCD forwhich trippingis ensuredfor residualsinusoidal
alternatingcurrents,whether suddenly appliedor slowlyrising.Thistype
isthemostfrequentlyusedonelectricalinstallations.
● RCD type A, RCD for which tripping is ensured for residual sinusoidal
alternating currents (like type AC) and residual pulsating direct currents
(DC), whether suddenly applied or slowly rising. It is not very used in
practice even if it is becoming more and more popular and in some
countriesitisrequestedbythenationalregulationinsteadoftypeAC.
● RCDtypeG=Generaltype(withouttripouttime-delay),forgeneraluse
andapplication.
OUTPUT
L
N
N
L
INPUT