Měřící Energetické Aparáty
14
e Current connection function checks currents for correct ow through individual
circuits of the instrument MEg40
+
and for correct direction, which must be in phase with
the voltage corresponding to the voltage input. e allowable phase shift is ± 80°. If no
current ows through the current input or its direction is turned relative to the voltage,
then the message Current connection error and active powers of the individual phases
will be displayed. According to the sign and size of the active power, you can determine
the error in the connection of the corresponding current. is function assumes a phase
current more than 3 % I
nom
at the rated voltage.
e last function checks voltages and currents of the individual phases for correct
assignment. If the voltage and current assignment is incorrect, the message Current
assignment error and phase shifts between U1-I1, U2-I2 and U3-I3 will be displayed.
e phase shifts in the realized wiring are expressed in degrees. is check is eective
when the power factor is higher than 0.65.
5/ INSTALLATION
e universal energy meter MEg40
+
shall be installed into a square hole of the panel
with the dimensions of 92 × 92 mm ± 1 mm to ensure access from both sides to the screw-
on terminals and a free space above and below the instrument to remove heat from the
instrument and install eccentrics, which attach the instrument to the panel mechanically.
White eccentrics are to be inserted into proled holes in the top and bottom of the black
housing of the instrument and turned towards the panel. To take out the eccentrics when
disassembling the instrument, turn the eccentrics backwards and remove from the holes.
e voltage inputs of the instrument MEg40
+
meet requirements of the measurement
category IV according to ČSN EN 61010-2-30 and can be connected directly to LV
collectors of the transformer station. In cases where the station includes a voltage circuit
protection or in cases where it is expected that voltage circuit protection will be realized
for other measuring instruments, the manufacturer recommends you to connect also
voltage inputs of the instrument MEg40
+
to the protected circuits. e measured voltages
U1, U2 and U3 in LV networks are to be connected through xed or exible wires with
the minimum cross-section of 0.75 mm
2
with double insulation.
Also in MV networks with resistance and compensated networks (MVL) and HV
networks, indirectly measured voltages U1, U2 and U3 are always connected to the phase
conductors and the measuring instrument measures phase or delta voltages according to
the programmed requirement. To the terminal Nm in MV, MVL and HV networks, the
ground is always applied. In LW networks, the central conductor is to be connected to
the terminal Nm.
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