GE 845 Instruction Manual page 261

CHAPTER 4: SETPOINTS
Table 4-45: IAC CURVE TRIP TIMES (IN SECONDS)
MULTIPLIER CURRENT (I/I
(TDM)
1.5
IAC EXTREMELY INVERSE
0.5 1.699
1.0 3.398
2.0 6.796
4.0 13.591
6.0 20.387
8.0 27.183
10.0 33.979
IAC VERY INVERSE
0.5 1.451
1.0 2.901
2.0 5.802
4.0 11.605
6.0 17.407
8.0 23.209
10.0 29.012
IAC INVERSE
0.5 0.578
1.0 1.155
2.0 2.310
4.0 4.621
6.0 6.931
8.0 9.242
10.0 11.552
IAC SHORT INVERSE
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
Where:
T = operate time (in seconds)
TDM = Multiplier setting
I = input current
I = Pickup Current setting
pickup
A to E = constants
t = characteristic constant
r
T = reset time in seconds (assuming energy capacity is 100% and RESET is
RESET
"Timed")
Table 4-44: GE TYPE IAC INVERSE TIME CURVE CONSTANTS
IAC CURVE SHAPE A
IAC Extremely Inverse 0.0040
IAC Very Inverse 0.0900
IAC Inverse 0.2078
IAC Short Inverse 0.0428
)
pickup
2.0 3.0 4.0
0.749 0.303 0.178
1.498 0.606 0.356
2.997 1.212 0.711
5.993 2.423 1.422
8.990 3.635 2.133
11.987 4.846 2.844
14.983 6.058 3.555
0.656 0.269 0.172
1.312 0.537 0.343
2.624 1.075 0.687
5.248 2.150 1.374
7.872 3.225 2.061
10.497 4.299 2.747
13.121 5.374 3.434
0.375 0.266 0.221
0.749 0.532 0.443
1.499 1.064 0.885
2.997 2.128 1.770
4.496 3.192 2.656
5.995 4.256 3.541
7.494 5.320 4.426
B C
0.6379 0.6200
0.7965 0.1000
0.8630 0.8000
0.0609 0.6200
5.0 6.0 7.0
0.123 0.093 0.074
0.246 0.186 0.149
0.491 0.372 0.298
0.983 0.744 0.595
1.474 1.115 0.893
1.966 1.487 1.191
2.457 1.859 1.488
0.133 0.113 0.101
0.266 0.227 0.202
0.533 0.453 0.405
1.065 0.906 0.810
1.598 1.359 1.215
2.131 1.813 1.620
2.663 2.266 2.025
0.196 0.180 0.618
0.392 0.360 0.337
0.784 0.719 0.674
1.569 1.439 1.348
2.353 2.158 2.022
3.138 2.878 2.695
3.922 3.597 3.369
PROTECTION
D E t
r
1.7872 0.2461 6.008
-1.2885 7.9586 4.678
-0.4180 0.1947 0.990
-0.0010 0.0221 0.222
8.0 9.0 10.0
0.062 0.053 0.046
0.124 0.106 0.093
0.248 0.212 0.185
0.495 0.424 0.370
0.743 0.636 0.556
0.991 0.848 0.741
1.239 1.060 0.926
0.093 0.087 0.083
0.186 0.174 0.165
0.372 0.349 0.331
0.745 0.698 0.662
1.117 1.046 0.992
1.490 1.395 1.323
1.862 1.744 1.654
0.160 0.154 0.148
0.320 0.307 0.297
0.640 0.614 0.594
1.280 1.229 1.188
1.921 1.843 1.781
2.561 2.457 2.375
3.201 3.072 2.969
4–157