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20
DANGER!
If an earth terminal is provided at the secondary side of the current transformer,
this must be connected to an earthing conductor!
In general, it is recommended that all current transformer circuits be earthed.
CAUTION!
The following must be observed to ensure safe and reliable operation:
- The connection of the current measurement inputs must be via an external,
electrically isolating current transformer.
- Overloading of the current transformers incorporated in the instrument must
be avoided. The maximum allowable continuous current is 6 A AC; transient
peaks 10 A.
These measures must be taken to ensure that the instrument is not damaged.
CAUTION!
The instrument terminals can become hot during operation.
- After the PQC has been operating, sufficient time must be allowed for the
instrument and its terminals to cool down before work is carried out on the
terminals.
Compliance with this stipulation will avoid the risk of burns.
Instrument types with single-phase measurement
[see Section 9, Instrument versions]
:
The current in any desired phase L is measured via an external, electrically isolating current
transformer.
[See Section 2, Technical data]
, for the measurement range.
The terminals L1 – S1-S2 are connected as shown in the connection diagram in
[
Figure 2
]
.
Instrument types with 3-phase measurement
[see Section 9, Instrument versions]
:
The currents in phases L1, L2 and L3 are measured via external, electrically isolating current
transformers.
See Section 2, Technical data, for the measurement range.
The terminals
L1 – S1-S2
,
L2 – S1-S2
and
L3 – S1-S2
must be connected as shown in the con-
nection diagram in
[Figure 3]
, in correct phase sequence.
Unassigned current measurement inputs can be left unconnected.
NOTE!
In networks with a nominal voltage of 1000 V and more, the regulations call for
the current transformer circuits to be earthed.
Note: In general, it is recommended that all current transformer circuits be
earthed.
If networks with a nominal voltage of 1000 V or over are left unearthed, damage
may occur to the instrument.
With three-phase measurement, automatic connection identification is not
possible.