TB MRI(K)3-C 03.02 E
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5.4.3 Voltage transformer connection for
residual voltage measuring
(3pha/e-n/1:1)
Depending on the connection of the voltage transformer
of ER/XR-relay types three possibilities of the
residual voltage measurement can be chosen (see 4.6).
5.4.4 Operation cycle counter
Each switch ON operation increase the counter. It is
possible to set the operation cycle counter to a start
value.
5.4.5 I
2*
t Operation cycle counter
The relay
MRI(K)3-C
provide a measurement unit to de-
terminate the switch off power of the circuit breaker.
They start from the point of set the trip output signal and
end until the point of the phase current is lower than
<2% of the nominal current. The max. record time for
each switch off operation is 2.54s. Each 20ms the
value of all three phases is measured. (Measured and
calculated in accordance to the HARR algorithm which
is used in all MR relay to determined the fundamental
wave.). The highest value of the three phase values is
stored and add to the composite value. The value of the
switch off power can be preset in case of the use of a
older CB with preceding load. To indicate that the max.
value of the switch off power is reached a alarm output
can be set. The indication take place be the means of a
LED and / or output relay. The max. possible value is
655,35 kAs
5.4.6 Rated -Frequency
The FFT-Algorithm used for the data acquisition needs
the set point of the rated frequency, i.e. 50 Hz or
60 Hz, for correct digital filtering of the earth current.
5.4.7 Indication of pickup
If the momentary current drops below the pickup thresh-
old, e.g I>, after the relay was activated and there was
no tripping, then the activation is signalled by short
flashing of LED I>. The LED keeps flashing until the
<RESET> push-button is pressed. By setting the parame-
ter to FLSH/NOFL, flashing can be suppressed.
5.4.8 Parameter Set Changeover Switch (P2)
By means of this switch two different parameter sets can
be activated. The changeover procedure can be real-
ised either by the software or via the digital input. If the
parameter set changeover switch is adjusted to ”SET2“,
the active parameter set can be changed to ”SET1“ via
the external input. If the changeover switch is set to
”SET1“, then it can be changed to ”SET2“ via the digital
input.
The digital input does not change this parameter. The
LED P2 on the front cover always indicates which of the
parameter sets is active.