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Device handbook SINEAX DM5000
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5.12 Fault current detection
Each fault current module provides
two channels
for monitoring differential or fault currents in earthed
AC current systems. In any case measurement has to be performed via suitable current transformers, a
direct measurement is not possible. The module is not suited for monitoring operating currents of normally
live conductors (L1, L2, L3, N).
Each channel provides two measurement ranges:
a)
Measurement range 1A
•
Application:
Direct measurement of a fault or earth wire current
•
Meas. transformer: Current transformer 1/1 bis 1000/1A; 0.2 up to 1.5VA;
Instrument security factor FS5
b)
Measurement range 2mA
•
Application:
Residual current monitoring (RCM)
•
Meas. transformer: Residual current transformer 500/1 up to 1000/1A
Rated burden 100 Ω / 0.025 VA up to 200 Ω / 0.06 VA
Use only transformers intended for this application, according to our current transformer
catalog, or transformers that fulfill the above specification. Using transformers with
divergent specifications may damage the measurement inputs.
Connection
The current transformers including the conductor isolation must guarantee in total a
reinforced or double insulation between the mains circuit connected on the primary side
and the measuring inputs of the device.
Only one measurement range may be connected per measuring channel!
The COM connectors of both measurement channels are internally connected.
For 2mA inputs a connection monitoring (breakage) is implemented. An alarm state is
signaled for the respective measurement channels if either the current transfomer is
disconnected or the connection to the transformer is interrupted.
