CHAPTER 5: SETTINGS GROUPED ELEMENTSB90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 5-1555Table 5-25: IEC curve trip times (in seconds)IAC curvesThe curves for the General Electric type IAC relay family are derived from the formulae:Eq. 5-7whereT = operate time (in seconds)TDM = Multiplier settingI = Input currentIpkp = Pickup Current settingMultiplier(TDM)Current ( I / I pickup)1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0IEC Curve A0.05 0.860 0.501 0.315 0.249 0.214 0.192 0.176 0.165 0.156 0.1490.10 1.719 1.003 0.630 0.498 0.428 0.384 0.353 0.330 0.312 0.2970.20 3.439 2.006 1.260 0.996 0.856 0.767 0.706 0.659 0.623 0.5940.40 6.878 4.012 2.521 1.992 1.712 1.535 1.411 1.319 1.247 1.1880.60 10.317 6.017 3.781 2.988 2.568 2.302 2.117 1.978 1.870 1.7820.80 13.755 8.023 5.042 3.984 3.424 3.070 2.822 2.637 2.493 2.3761.00 17.194 10.029 6.302 4.980 4.280 3.837 3.528 3.297 3.116 2.971IEC Curve B0.05 1.350 0.675 0.338 0.225 0.169 0.135 0.113 0.096 0.084 0.0750.10 2.700 1.350 0.675 0.450 0.338 0.270 0.225 0.193 0.169 0.1500.20 5.400 2.700 1.350 0.900 0.675 0.540 0.450 0.386 0.338 0.3000.40 10.800 5.400 2.700 1.800 1.350 1.080 0.900 0.771 0.675 0.6000.60 16.200 8.100 4.050 2.700 2.025 1.620 1.350 1.157 1.013 0.9000.80 21.600 10.800 5.400 3.600 2.700 2.160 1.800 1.543 1.350 1.2001.00 27.000 13.500 6.750 4.500 3.375 2.700 2.250 1.929 1.688 1.500IEC Curve C0.05 3.200 1.333 0.500 0.267 0.167 0.114 0.083 0.063 0.050 0.0400.10 6.400 2.667 1.000 0.533 0.333 0.229 0.167 0.127 0.100 0.0810.20 12.800 5.333 2.000 1.067 0.667 0.457 0.333 0.254 0.200 0.1620.40 25.600 10.667 4.000 2.133 1.333 0.914 0.667 0.508 0.400 0.3230.60 38.400 16.000 6.000 3.200 2.000 1.371 1.000 0.762 0.600 0.4850.80 51.200 21.333 8.000 4.267 2.667 1.829 1.333 1.016 0.800 0.6461.00 64.000 26.667 10.000 5.333 3.333 2.286 1.667 1.270 1.000 0.808IEC Short Inverse0.05 0.153 0.089 0.056 0.044 0.038 0.034 0.031 0.029 0.027 0.0260.10 0.306 0.178 0.111 0.088 0.075 0.067 0.062 0.058 0.054 0.0520.20 0.612 0.356 0.223 0.175 0.150 0.135 0.124 0.115 0.109 0.1040.40 1.223 0.711 0.445 0.351 0.301 0.269 0.247 0.231 0.218 0.2070.60 1.835 1.067 0.668 0.526 0.451 0.404 0.371 0.346 0.327 0.3110.80 2.446 1.423 0.890 0.702 0.602 0.538 0.494 0.461 0.435 0.4151.00 3.058 1.778 1.113 0.877 0.752 0.673 0.618 0.576 0.544 0.518
