For inverse-time operation, both IEC and ANSI/IEEE standardized inverse-time characteristics are supported.
The operate times for the ANSI and IEC IDMT curves are defined with the coefficients A, B and C.
The values of the coefficients can be calculated according to the formula:
t[s] | Operate time in seconds |
I | Measured current |
I> | Set Start value |
k | Set Time multiplier |
Curve name | A | B | C |
---|---|---|---|
(1) ANSI Extremely Inverse | 28.2 | 0.1217 | 2.0 |
(2) ANSI Very Inverse | 19.61 | 0.491 | 2.0 |
(3) ANSI Normal Inverse | 0.0086 | 0.0185 | 0.02 |
(4) ANSI Moderately Inverse | 0.0515 | 0.1140 | 0.02 |
(6) Long Time Extremely Inverse | 64.07 | 0.250 | 2.0 |
(7) Long Time Very Inverse | 28.55 | 0.712 | 2.0 |
(8) Long Time Inverse | 0.086 | 0.185 | 0.02 |
(9) IEC Normal Inverse | 0.14 | 0.0 | 0.02 |
(10) IEC Very Inverse | 13.5 | 0.0 | 1.0 |
(11) IEC Inverse | 0.14 | 0.0 | 0.02 |
(12) IEC Extremely Inverse | 80.0 | 0.0 | 2.0 |
(13) IEC Short Time Inverse | 0.05 | 0.0 | 0.04 |
(14) IEC Long Time Inverse | 120 | 0.0 | 1.0 |