Rockwell Automation SD3000 Drive Configuration, Programming - Manual (Page 104)

Appendix F
(Continued)
To determine how low full load current can go before the gain will be limited, and resolution degraded, use
the following equation:
I_full_low_limit = CT / ( 10.2 * (I-limit + 75%))
Using the same CT ratio of 2000:1, the low limit of full load current is 87 amps. If your full load current is less
than the result of this calculation, and you do not want to sacrifice current feedback resolution, you must use
a CT with fewer turns on the secondary or add more turns to the primary to lower the overall CT ratio.
To determine how high full load current can go before the gain will be limited, use the following equation:
I_full_high_limit = (CT * 255) / (10.2 * 26 *(l-limit + 75%))
Using the same CT ratio of 2000:1, the high limit of full load current is 855A. If your full load current is greater
than the result of this calculation, you must use a CT with more turns on the secondary or remove turns from
the primary to raise the overall CT ratio.
F-2