ABB 615 series Technical Manual page 656

Section 4
Protection functions
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GUID-6FC7624E-7E13-4645-8943-0FDFBAA1D184 V1 EN
Figure 323: Trip time curves for the overexcitation IDMT curve 4 ("OvExt IDMT Crv4")
for different values of the Time multiplier setting when the Constant delay
is 800 milliseconds
The activation of the TRIP output activates the BLK_RESTART output.
If the excitation level increases above the set value when BLK_RESTART is active, the
TRIP output is activated immediately.
If the excitation level increases above the set value when BLK_RESTART is not active but
COOL_ACTIVE is active, the TRIP output is not activated instantly. In this case, the
remaining part of the cooling timer affects the calculation of the operation timer as shown
in Figure 324. This compensates for the heating effect and makes the overall trip time
shorter.
1MAC059074-MB A
615 series ANSI
Technical Manual