GE M60 - Page 464

5-256 M60 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
GROUPED ELEMENTS CHAPTER 5: SETTINGS
5
Table 5-38: IEEE curve trip times (in seconds)
IEC curves
For European applications, the relay offers three standard curves defined in IEC 255-4 and British standard BS142. These
are defined as IEC Curve A, IEC Curve B, and IEC Curve C. The IEC curves are derived by the operate and reset time
equations.
Eq. 5-41
where
T = operate time (in seconds)
TDM = Multiplier setting
I = input current
I
pickup
= Pickup Current setting
K, E = constants defined in the table
t
r
= characteristic constant defined in the table
T
RESET
= reset time in seconds (assuming energy capacity is 100% and RESET is “Timed”)
Table 5-39: IEC (BS) inverse time curve constants
Multiplier
(TDM)
Current ( I / I
pickup
)
1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
IEEE Extremely Inverse
0.5 11.341 4.761 1.823 1.001 0.648 0.464 0.355 0.285 0.237 0.203
1.0 22.682 9.522 3.647 2.002 1.297 0.927 0.709 0.569 0.474 0.407
2.0 45.363 19.043 7.293 4.003 2.593 1.855 1.418 1.139 0.948 0.813
4.0 90.727 38.087 14.587 8.007 5.187 3.710 2.837 2.277 1.897 1.626
6.0 136.090 57.130 21.880 12.010 7.780 5.564 4.255 3.416 2.845 2.439
8.0 181.454 76.174 29.174 16.014 10.374 7.419 5.674 4.555 3.794 3.252
10.0 226.817 95.217 36.467 20.017 12.967 9.274 7.092 5.693 4.742 4.065
IEEE Very Inverse
0.5 8.090 3.514 1.471 0.899 0.654 0.526 0.450 0.401 0.368 0.345
1.0 16.179 7.028 2.942 1.798 1.308 1.051 0.900 0.802 0.736 0.689
2.0 32.358 14.055 5.885 3.597 2.616 2.103 1.799 1.605 1.472 1.378
4.0 64.716 28.111 11.769 7.193 5.232 4.205 3.598 3.209 2.945 2.756
6.0 97.074 42.166 17.654 10.790 7.849 6.308 5.397 4.814 4.417 4.134
8.0 129.432 56.221 23.538 14.387 10.465 8.410 7.196 6.418 5.889 5.513
10.0 161.790 70.277 29.423 17.983 13.081 10.513 8.995 8.023 7.361 6.891
IEEE Moderately Inverse
0.5 3.220 1.902 1.216 0.973 0.844 0.763 0.706 0.663 0.630 0.603
1.0 6.439 3.803 2.432 1.946 1.688 1.526 1.412 1.327 1.260 1.207
2.0 12.878 7.606 4.864 3.892 3.377 3.051 2.823 2.653 2.521 2.414
4.0 25.756 15.213 9.729 7.783 6.753 6.102 5.647 5.307 5.041 4.827
6.0 38.634 22.819 14.593 11.675 10.130 9.153 8.470 7.960 7.562 7.241
8.0 51.512 30.426 19.458 15.567 13.507 12.204 11.294 10.614 10.083 9.654
10.0 64.390 38.032 24.322 19.458 16.883 15.255 14.117 13.267 12.604 12.068
IEC (BS) curve shape K E t
r
IEC Curve A (BS142) 0.140 0.020 9.7
IEC Curve B (BS142) 13.500 1.000 43.2