Manual MRN3 GB
Woodward
TD_MRN3_09.08_GB_Rev.New
37
6.3 Checking the set values
By repeatedly pressing the push button <SELECT>, all relay set values may be checked. Set value
modification can be done with the push button <+><-> and <ENTER>. For detailed information
about that, please refer to chapter 4.3 of the description “MR – Digital multifunctional re-lays”.
As relay input energizing quantities, three phase voltages should be applied to MRN3 relay input
circuits. Depending on the system conditions and the voltage transformer used, three voltages can
be connected to the relay input circuits with either star or delta connection. In case of a star con-
nection the phase-to-neutral voltage will be applied to the voltage input circuits, while the phase-to-
phase voltages will be connected to the voltage input circuits in case of a delta connection. The vol-
tage in-put connection must be set as a parameter, and should correspond with the actual voltage
input connection:
Star connection:
Phase-to-neutral voltages will be measured and evaluated.
Delta connection:
Phase-to-phase voltages will be measured and evaluated.
6.4 Secondary
injection
test
6.4.1 Test equipment
•
Voltmeter and frequency meter with class 1 or better,
•
auxiliary power supply with the voltage corresponding to the rated data on the type plate,
•
three-phase voltage supply unit with frequency regulation (Voltage: adjustable from
0 to 2 x UN; Frequency: adjustable from 40 - 70 Hz),
•
timer to measure the operating time (Accuracy class 10 ms),
•
switching device and Test leads and tools
