Eaton EMR-3MP0 Installation, Operation And Maintenance Manual page 178

4 Protective Elements
4.10 46 - Current Unbalance Protection
Having tripped the relay in the previous test, now decrease the phase A current. The
dropout ratio must not be higher than 0.97 times the threshold value.
Testing %(I2/I1)
• Configure minimum threshold value »Threshold« (I2 Fund.) (0.01 x In) and set »%
(I2/I1)« greater or equal to 10%.
• Apply a balanced three-phase current system (nominal currents). The measuring
value of »%(I2/I1)« should be 0%.
• Now increase the phase A current. With this configuration, the threshold
value »Threshold« (I2 Fund.) should be reached before the value »%(I2/I1)« reaches
the set »%(I2/I1)« ratio threshold.
• Continue increasing the phase 1 current until the relay is activated.
Testing the dropout ratio of %(I2/I1)
Having tripped the relay in the previous test, now decrease the phase A current. The
dropout of »%(I2/I1)« has to be 1% below the »%(I2/I1)«setting.
Successful test result:
The measured trip delays, threshold values, and dropout ratios are within the permitted
deviations/tolerances, specified under Technical Data.
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