Manual MRIK3-C EN
Woodward
DOK-TD-MRIK3-C Rev. A
41
6.4.5
I2*t Operation cycle counter
The relay MRIK3-C provide a measurement unit to determinate 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 opera-
tion 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 determine the fundamental
wave.). The highest value of the three phase values is stored and added 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
6.4.6
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.
6.4.7
Indication
of
pickup
If the momentary current drops below the pickup threshold, 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 parameter to
FLSH/NOFL, flashing can be suppressed.
6.4.8
Parameter Set Changeover Switch (P2)
By means of this switch two different parameter sets can be activated. The changeover procedure
can be realised 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 in-
put.
The digital input does not change this parameter. The LED P2 on the front cover always indicates
which of the parameter sets is active.