Appendix G Reset Curve Timing Tables
Reset times (T) for IEEE Reset Curves can be calculated using the following formula.
IEEE Moderately Inverse
T= 4.85* Time Multiplier / (M² - 1)
IEEE Very Inverse
T= 21.6* Time Multiplier / (M² - 1)
IEEE Extremely Inverse
T= 29.1* Time Multiplier / (M² - 1)
If the Reset Curve starting point is set to Reset Threshold,
M = (Measured Current) / (Reset Threshold x Pickup Current).
If the Reset Curve starting point is set to Pickup,
M = (Measured Current) / (Pickup Current).
Tables listing the reset times in seconds for IEEE Reset Curves are given below.
Table 111 IEEE Reset Curves Timing Table
|
% of Setting Current |
IEEE Inverse |
IEEE Very Inverse |
IEEE Extremely Inverse |
|---|---|---|---|
|
0% |
4.85 |
21.60 |
29.10 |
|
5% |
4.86 |
21.65 |
29.17 |
|
10% |
4.90 |
21.82 |
29.39 |
|
15% |
4.96 |
22.10 |
29.77 |
|
20% |
5.05 |
22.50 |
30.31 |
|
25% |
5.17 |
23.04 |
31.04 |
|
30% |
5.33 |
23.74 |
31.98 |
|
35% |
5.53 |
24.62 |
33.16 |
|
40% |
5.77 |
25.71 |
34.64 |
|
45% |
6.08 |
27.08 |
36.49 |
|
50& |
6.47 |
28.80 |
38.80 |
|
55% |
6.95 |
30.97 |
41.72 |
|
60% |
7.58 |
33.75 |
45.47 |
|
65% |
8.40 |
37.40 |
50.39 |
|
70% |
9.51 |
42.35 |
57.06 |
|
75% |
11.09 |
49.37 |
66.51 |
|
80% |
13.47 |
60.00 |
80.83 |
|
85% |
17.48 |
77.84 |
104.86 |
|
90% |
25.53 |
113.68 |
153.16 |
|
95% |
49.74 |
221.54 |
298.46 |
|
99% |
243.72 |
1085.43 |
1462.31 |
Reset times (I) for IEC 255 Reset Curves can be calculated using the following formula.
IEC 255 Inverse
T= 13.5* Time Multiplier / (M² - 1)
IEC 255 Very Inverse
T= 47.3* Time Multiplier / (M² - 1)
IEC 255 Extremely Inverse
T= 80* Time Multiplier / (M² - 1)
If the Reset Curve starting point is set to Reset Threshold,
M = (Measured Current) / (Reset Threshold x Pickup Current).
If the Reset Curve starting point is set to Pickup,
M = (Measured Current)/(Pickup Current)
Tables listing the reset times in seconds for IEC 255 Reset Curves are given below.
Table 112 IEC 255 Reset Curves Timing Table
|
% of Setting Current |
IEC 255 Inverse |
IEC 255 Very Inverse |
IEC 255 Extremely Inverse |
|---|---|---|---|
|
0% |
13.50 |
47.30 |
80.00 |
|
5% |
13.53 |
47.42 |
80.20 |
|
10% |
13.64 |
47.78 |
80.81 |
|
15% |
13.81 |
48.39 |
81.84 |
|
20% |
14.06 |
49.27 |
83.33 |
|
25% |
14.40 |
50.45 |
85.33 |
|
30% |
14.84 |
51.98 |
87.91 |
|
35% |
15.38 |
53.90 |
91.17 |
|
40% |
16.07 |
56.31 |
95.24 |
|
45% |
16.93 |
59.31 |
100.31 |
|
50& |
18.00 |
63.07 |
106.67 |
|
55% |
19.35 |
67.81 |
114.70 |
|
60% |
21.09 |
73.91 |
125.00 |
|
65% |
23.38 |
81.90 |
138.53 |
|
70% |
26.47 |
92.75 |
156.86 |
|
75% |
30.86 |
108.11 |
182.86 |
|
80% |
37.50 |
131.39 |
222.22 |
|
85% |
48.65 |
170.45 |
288.29 |
|
90% |
71.05 |
248.95 |
421.05 |
|
95% |
138.46 |
485.13 |
820.51 |
|
99% |
678.39 |
2376.88 |
4020.10 |