| The basis for the AC/DC-sensitive device comprises a pulsating current-sensitive protective switching unit with a release that
operates independently. The following diagram shows the fundamental construction. |
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The summation current transformerW1 constantly monitors the electrical installation for alternating and pulsating formed fault currents. The summation current transformer W2detects
the smooth DC fault currents and gives a swith-off signal via the electronic unit E to the releaseA.
For the purpose of a highly secure supply, the power supply for the electronic unit comes from all three phase conductors and the neutral conductor. Besides,it is designed such that the electronics still operate at a voltage reduction of 70% (e.g.between phase conductor and neutral conductor).
Consequently the tripping due to smooth DC fault current is provided for whenever such forms of fault current appear, also during disturbances of the electric supply network.
E.g.when the neutral conductor is interrupted. Even in the extremely improbable case that two phase conductors and the neutral conductor are lost and the remaining intact phase conductor is a fire hazard due to an earth fault, protection is then provided by the pulsating current sensitive swithing
part which,due to its supply-independent release, reliably switches the RCCB off. |
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A Release
M Mechanice of the protective device
E Electronics for tripping smooth DC fault currents
T Test hutton
N Secondary winding
W2 Summation transformer for detection of smooth DC Fault currents |
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The POPP supplies range studied to meet all the requirements concerning electrical installations consists of two main product families:
AC type: Residual Current operated Circuit-breakers(RCCBs)for AC fault currents;
Atype :Residual Current operated Circuit-Breakers(RCCBs) forAC and pulsating DC fault currents.
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