ABB RELION REX640 Technical Manual page 853

1MRS759142 F
phases match with the set
the Timer.
Timer
Once activated, the Timer activates the START output. Depending on the value of
the set
or IDMT.
When the operation timer has reached the value set by
mode or the maximum value defined by the IDMT, the OPERATE output is activated.
When the user-programmable IDMT curve is selected, the operate time
characteristics are defined by the parameters
B , Curve parameter C , Curve parameter D and Curve parameter E .
If a drop-off situation occurs, that is, a fault suddenly disappears before the operate
delay is exceeded, the reset state is activated. The behavior in the drop-off situation
depends on the selected operate time characteristics. If the DT characteristics are
selected, the reset timer runs until the set
the drop-off situation exceeds the set
START output is deactivated.
When the IDMT operate time curve is selected, the functionality of the Timer in the
drop-off state depends on the combination of the
reset and Reset delay time settings.
Table 780: Reset time functionality when IDMT operation time curve selected
Reset functionality
Instantaneous
reset
Frozen timer
Linear decrease
REX640
Technical Manual
Num of start phases , the phase selection logic activates
Operating curve type , the time characteristics are selected according to DT
For a detailed description of the voltage IDMT curves, see
IDMT curves for overcurrent protection
Operation timer
is "Reset instan-
taneously" when
drop-off occurs
Operation timer
is frozen during
drop-off
Operation timer
value linearly de-
creases during
the drop-off sit-
uation
in this manual.
Operate delay time in the DT
Curve parameter A , Curve parameter
Reset delay time value is exceeded. If
Reset delay time , the Timer is reset and the
Type of reset curve , Type of time
Setting Type of Setting Type of
reset curve time reset
"Immediate" Setting has no
effect
"Def time reset" "Freeze Op tim-
er"
"Def time reset" "Decrease Op
timer"
Protection functions
Chapter 11.2.1
Setting Reset
delay time
Setting has no
effect
Operate timer is
reset after the
Reset delay
set
time has elapsed
Operate timer is
reset after the
Reset delay
set
time has elapsed
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