gefran GTF-Xtra Installation And Operation Manual page 21

RMS current limit
The option for controlling the load current limit is available in all work modes.
If the current value exceeds the limit (settable in the nominal full-scale range) in mode PA the conduction angle is limited,
while in zero-crossing mode (ZC, BF, HSC) the cycle time conduction percentage is limited.
This limitation ensures that the RMS value (i.e., not the instantaneous value) of the load current does NOT exceed the
set RMS current limit.
Figure 25
DT
"Delay triggering" (for ZC, BF control modes only) Settable from 0° to 90°.
Useful for inductive loads (transformer primaries) to prevent current peak that in certain cases could trip the high-speed
fuses that protect the SCRs
Figure 26
80994B_MHW_GTF-Xtra_05-2016_ENG
Example of conduction angle limitation in PA mode to respect an
RMS current limit below the nominal current of the load.
Transient with
Over-Current
Example of firing of inductive load with/without delay-triggering.
Transient without
Over-Current
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