11.3.1 IDMT curves for overvoltage protection
In inverse-time modes, the operate time depends on the momentary value of the
voltage, the higher the voltage, the faster the operate time. The operate time
calculation or integration starts immediately when the voltage exceeds the set value
of the
Start value
setting and the START output is activated.
The OPERATE output of the component is activated when the cumulative sum of the
integrator calculating the overvoltage situation exceeds the value set by the inverse
time mode. The set value depends on the selected curve type and the setting values
used. The user determines the curve scaling with the
Time multiplier
setting.
The
Minimum operate time
setting defines the minimum operate time for the IDMT
mode, that is, it is possible to limit the IDMT based operate time for not becoming
too short. For example:
Figure 1012: Operate time curve based on IDMT characteristic with Minimum
operate time set to 0.5 second
General function block features
1MRS759142 F
1896 REX640
Technical Manual
To Next Page
Loading...
