2.2.8.1
Phase and Ground Current Measuring Input Cards
For the EMR-3MP0, there are two measuring cards available, the standard phase and
ground current card “TI”, and a special MP‑3000-compatible current input card “TI‑MP”.
Both cards are different with respect to the mechanical layout, and there is one important
difference with respect to the terminals:
• The standard phase and ground current card “
” has measuring inputs for 1 A and
5 A CTs.
• The MP‑3000-compatible current input card “
” has measuring inputs only for
5 A CTs.
Either card is provided with 4 current measuring inputs: three for measuring the phase
currents and one for measuring the earth current.
The input for earth current measuring either can be connected to a cable-type current
transformer or alternatively it is possible to connect the summation current path of the
phase current transformer to this input (Holmgreen connection).
DANGER!
Current transformers have to be earthed on their secondary side.
DANGER!
Interrupting the secondary circuits of current transformers causes hazardous voltages.
The secondary side of the current transformers have to be short circuited before the
current circuit to the device is opened.
DANGER!
The current measuring inputs may exclusively be connected to current measuring
transformers (with galvanic separation).
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EMR-3MP0
2 Hardware
2.2 EMR-3MP0 – Installation and Wiring
